REESE  LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 

Deceived  J^r. 

Accession  No.jjlOo      .   Cla&s  No. 


OF  THE  '  f 

UNIVERSITY 


American 
Cements . . 


BY 


Uriah  Cumming-s, 


BOSTON : 

ROGERS  &  MANSON. 

1808. 


COPYRIGHTED,  1898, 
BY  ROGERS  &  MANSON. 


PREFACE. 


in  a  subject  so  large  as  that  to  which  the  present  treatise  is  devoted 
it  will  not  be  regarded  as  strange  that  there  are  controverted  points 
and  matters  concerning  which  the  authorities  are  not  in  harmony. 

The  multitude  of  facts  which  must  be  taken  into  consideration 
readily  accounts  for  these  divergences  of  opinion. 

In  that  portion  of  the  present  work  which  has  to  do  with  the 
theoretical  and  chemical  side  of  this  very  practical  subject  special 
reference  is  made,  and  special  attention  given,  to  such  branches  of  the 
subject  as  are  particularly  matters  of  doubt,  of  conjecture,  and  of 
controversy. 

A  full  and  free  discussion  of  such  points  has  been  thought  de- 
sirable. 

In  the  conclusions  reached  in  the  present  treatise  concerning  the 
various  silicates  of  which  natural  and  other  cements  are  made  up,  and 
in  regard  to  matters  wherein  the  present  writer  notes  his  dissent  from 
the  ordinarily  accepted  hypotheses,  it  is  believed  that  the  theories,  if 
such  they  may  be  termed,  which  are  here  advanced,  account  for  by 
far  the  greater  proportion  of  those  incontestable  facts  which  come  to 
the  view  of  every  investigator,  and  which  must  not  be  ignored,  but 
rather  accounted  for,  and  accorded  a  place  in  any  worthy  system. 

The  chief  motive,  however,  which  has  animated  the  present  work, 
has  been  a  desire  to  see  adequate  consideration  paid  to  the  claims  and 
merits  of  American  rock  cements. 

It  has  always  seemed  to  the  present  writer  that  scant  justice  has 
been  done  to  natural  hydraulic  cements,  and  that  the  tendency  to  re- 
gard artificial  products  as,  in  some  mysterious  manner,  much  superior 
to  all  others  has  no  sufficient  justification  in  the  facts  of  the  case, 
and  that  when  all  the  evidence  is  heard  it  will  be  found  and  conceded, 
that  for  enduring  qualities,  for  excellence  in  places  of  trial,  for  per- 
manence, and  for  worth,  no  artificially  made  cement  can  be  found  to 
compare  with  that  mixed  in  the  moulds  of  nature. 


4  PREFACE. 

The  writer  has  not  hoped  to  carry  the  assent  of  the  reader  at 
every  step.  He  will  feel  amply  repaid  if  any  words  of  his  find  favor, 
or  provoke  sufficient  discussion  to  lead  to  a  much-needed  inquiry 
along  the  lines  which  he  has  -scarcely  more  than  suggested.  In  this 
way  much  truth  may  be  brought  to  light. 

Aside,  however,  from  the  theoretical  aspect  of  the  subject,  it  has 
been  thought  to  be  a  matter  of  great  importance  to  bring  to  the  atten- 
tion of  the  reader,  in  some  convenient  form,  much  matter  of  a  practical 
nature  which  has  never  found  a  place  in  any  of  the  printed  works. 

Within  these  pages  it  is  hoped  that  the  manufacturer,  and  the 
practical  e very-day  user  of  cements,  who  care  little  or  nothing  for  the 
chemical  nature  of  the  product  they  handle,  will  find  hints  and  aids 
which  may  be  of  value,  and  information  which  cannot  readily  be 
found  elsewhere. 

And  finally,  if  a  further  word  is  necessary  to  justify  the  present 
attempt,  attention  is  called  to  the  fact,  that  since  the  publication  of 
Gen.  Q.  A.  Gillmore's  most  excellent  book,  written  some  thirty-five 
years  ago,  no  work  whatever  has  been  produced  which  deals  with 
the  subject  of  American  rock  cements. 

This  period  has  been  by  far  the  most  important  in  the  history  of 
the  industry.  The  changes  which  have  taken  place  during  this  time, 
the  marked  advances  which  have  been  made,  the  new  processes  which 
are  being  employed,  and  the  marvellous  growth  of  the^trade,  resulting 
from  a  rapid  widening  of  the  markets  for  the  product,  clearly  present 
a  profitable  field  for  investigation  and  furnish  many  facts  worthy  of 
record. 

URIAH   CUMMINGS. 
STAMFORD,  CONN.,  1898. 


CONTENTS. 

Preface 


CHAPTER  I. 

Introductory  and  historical        ............  T  r 

Smeaton  and  his  discoveries      ............  I2 

The  cements  of  the  ancients     ............  T3 

European  cements        ...............  T  7 

Portland  cement  first  produced      ...........  l8 

American  Rock  cement  first  produced   .........  18 

European  Rock  cement    ..............  23 

CHAPTER  II. 

Common  quicklime      ...............  25 

Hydraulic  lime    .     .     .     .     .     ............  26 

Hydraulic  cement    ................  27 

Hints  concerning  calcination     ............  2& 

CHAPTER  III. 

Silicates     ...................  3° 

Effect  of  excess  in  bases      .............  3  l 

Effect  of  high  heat  in  calcination       ..........  32 

Alkalies      ............     .......  33 

Chemical  combinations    ..............  34 

CHAPTER  IV. 

Analyses  of  American  and  European  cements     ......  35 

Table  of  reference      ...............  36 

Eminent  analysts  consulted       ...........     •  3  8 

CHAPTER  V. 

Ancient  Greek  and  Roman  mortars  ..........  39 

Carbonate  of  lime  mortars  '.     ............  43 

5 


CONTENTS. 


Concrete  of  the  Mound-Builders .     .  44 

Old  stone  mill  at  Newport,  R.  I 45 

Infiltration  process 48 

Ancient  and  modern  sulphate  of  lime  mortars 49 

CHAPTER  VI. 

The  chemistry  of  cements 54 

Opinions  of  the  leading  authorities 55 

Effects  of  magnesia  in  a  cement 61 

Practical  experiments 63 

Relative  values  of  lime  and  magnesia  as  a  flux .  67 

Adulteration  of  cements 68 

Combining  ratio  of  the  various  silicates 76 

Analyzation  of  analyses 77 

Conflicting  opinions  as  to  the  formation  of  silicates     ....  84 

Magnesian  cements  not  inferior  to  lime  cements 86 

Table  of  atomic  weights „  88 

Method  of  calculating  chemical  combinations 89 

High  tests  by  use  of  sulphate  of  lime 90 

Rapid  crystallization  injurious 95 

CHAPTER  VII. 

Various  methods  of  testing 96 

Cements  improved  by  hydration 98 

Specifications  of  United  States  engineers,  and  others  ......  99 

Cement  testing  —  by  Cecil  B.  Smith ,115 

Professor  Porter  on  cement  testing .     ...  163 

Cement-testing  machines 172 

Prejudice  against  domestic  Portland  cement 183 

Rock  and  Portland  cements  —  difference  in  manufacture      .     .  184 

Short-time  tests  deceptive 185 

Briquettes  become  brittle  with  age 189 

Prediction  as  to  future  specifications 190 

An  ideal  cement 192 

High  short  tests  followed  by  weakness 194 

Results  of  freezing 196 


CONTENTS.  7 

PAGE 

The  color  whim 197 

Absurdities  in  tensile  tests 199 

Passing  of  the  high-test  craze .  209 

CHAPTER  VIII. 

Manufacture  of  Rock  cement  in  United  States  .     .     .     .     .     .  210 

Rock  cements  in  New  England 211 

European  writers  and  their  American  imitators       .     .      .     .     .  212 

Kinds  of  packages  in  use 213 

Crushing  and  milling  machinery 214 

Typical  cement  works  illustrated 220 

CHAPTER  IX. 

The  uses  of  cement .  264 

Increasing  use  per  capita 264 

Use  of  concrete  growing  in  favor „  265 

Impure  sand  —  its  effect  in  mortars 268 

"  Sand  "  cement 269 

Weights  of  cement  —  different  standards        270 

Table  of  weights  and  measures 271 

Volume  vs.  weight 272 

Ultimate  strength  of  Rock  and  Portland  cements        ....  273 

Machine  vs.  hand-made  mortars 274 

Mortar-making  as  witnessed  by  the  author     . 275 

Effects  of  poorly  made  mortars 277 

A  rare  collection  of  ancient  mortars 278 

Thoughts  on  stone-making „ 280 

By  natural  infiltration 280 

By  artificial  infiltration 282 

By  natural  deposition , 283 

Statistics    . 287 

Total  production  of  Rock  cement  in  United  States      ....  288 

Portland  cement  —  imported  and  domestic     .......  289 

Product  of  Rock  cement  1895  and  1896 290 

Notable  structures  laid  in  American  Rock  cements      .     ,     .     .  29 [ 

A  WONDERFUL  RECORD 299 


ILLUSTRATIONS. 


PAGE 


Views  of  Fractured  Sections  of  Cement  Briquettes,        166,  168,  169 
Automatic  Cement  Testing  Machine,  Designed  by  J.  M.  Porter,   172 

Lafayette  College  Testing  Laboratory. 

Fairbanks  Cement  Testing  Machine 177 

Riehle  Standard  Cement  Testing  Machine  .     .     .      .     „     ,     .     .   179 
Cummings  Hydrostatic  Cement  Tester .     .     .181 

Capacity,  300  Ibs. 

Cummings  Hydrostatic  Tester 182 

Capacity,  1,500  Ibs. 

Sturtevant  Roll  Jaw  Rock  Breaker  and  Fine  Crusher  .     .     .     .214 

Sturtevant  Rock  Emery  Mill  Stone 216 

Sturtevant  Rock  Emery  Mill 217 

The  Clark  Mills,  Utica,  111 220,  221 

The  Cummings  Cement  Works,  Akron,  N.  Y.    .     225,  229,  231,  233 

The  Louisville  Cement  Works,  Louisville,  Ky .237,  241 

The  Lawrence  Cement  Works,  Rosendale,  N.  Y 245,  249 

The    Empire    Portland    Cement   Works,  Warners,   N.  Y., 

255»  257,  259,  261 
Cockburn  Continuous  Concrete  Mixer 


AMERICAN   CEMENTS. 


CHAPTER    I. 

INTRODUCTORY  —  HISTORICAL — SMEATON  AND  HIS  DISCOVERIES  — 
THE  CEMENTS  OF  THE  ANCIENTS  —  EUROPEAN  CEMENTS  — 
AMERICAN  CEMENTS. 

In  order  to  arrive  at  an  understanding  of  the  nature  of  American 
rock  cements,  and  to  be  able  to  judge  accurately,  or  even  approxi- 
mately, as  to  the  position  these  cements  occupy  in  the  world,  and  the 
relations  they  bear  to  the  natural  and  artificial  cements  of  Europe, 
together  with  the  time  of  their  first  fabrication,  and  the  uses  that  were 
made  of  them,  and  to  fairly  comprehend  the  state  of  the  art  from  its 
earliest  inception  until  the  present  time,  it  will  be  necessary  to  take  a 
glance  at  the  history  of  this  important  building  material,  even  though 
it  be  a  cursory  one. 

It  seems  to  be  conceded  by  all  European  authorities  that  John 
Smeaton,  C.  E.,  of  England,  was  the  first  to  discover  the  source  of 
hydraulicity  in  certain  limestones.  The  discovery  was  made  in  the 
year  1756,  while  casting  about  for  a  reliable  mortar  to  be  used  in 
the  construction  of  the  Eddystone  Lighthouse.  It  appears  that  prior 
to  that  date  nothing  was  known  as  to  the  hydraulic  character  of  the 
impure  limestones  of  the  blue  lias  formation  which  extends  through 
several  counties  in  England. 

In  the  year  named,  Smeaton  discovered,  during  the  course  of 
many  experiments,  that  the  cause  of  the  hydraulicity  of  a  limestone 
was  due  to  the  presence  of  clay  in  the  stone. 

Pasley,  in  the  preface  to  his  work,  dated  Sept.  17,  1838,  says  of 
Smeaton  that  "  he  was  the  first  who  discovered,  in  or  soon  after 
the  year  1756,  that  the  real  cause  of  the  water-acting  properties 
of  limes  and  cements  consisted  in  a  combination  of  clay  with  the  car- 
bonate of  lime,  in  consequence  of  having  ascertained  by  a  very  simple 


12  AMERICAN    CEMENTS. 

sort  of  chemical  analysis,  that  there  was  a  proportion  of  the  former 
ingredient  in  all  the  natural  limestones  which,  on  being  calcined, 
developed  that  highly  important  quality,  without  which,  walls  exposed 
to  water  go  to  pieces,  and  those  exposed  to  air  and  weather  only  are 
comparatively  of  inferior  strength. 

"By  this  memorable  discovery,  Smeaton  overset  the  prejudices  of 
more  than  two  thousand  years,  adopted  by  all  writers,  from  Vitru- 
vius  in  ancient  Rome  to  Belidor  in  France,  and  Semple  in  this  coun- 
try (England),  who  agreed  in  maintaining  that  the  superiority  of  lime 
consisted  in  the  hardness  and  whiteness  of  the  stone,  the  former  of 
which  may  or  may  not  be  accompanied  by  water-setting  or  powerful 
cementing  properties,  and  the  latter  of  which  is  absolutely  incom- 
patible with  them. 

"The  new  principle  laid  down  by  Smeaton,  the  truth  of  which 
has  recently  been  admitted  by  the  most  enlightened  chemists  and 
engineers  of  Europe,  was  the  basis  of  the  attempts,  by  Dr.  John  at 
Berlin  and  M.  Vicat  (the  engineer)  in  France,  to  form  an  artificial 
water  lime  or  hydraulic  lime  in  1818,  and  of  mine  to  form  an  artificial 
water  cement  at  Chatham  in  1826,  to  which  I  was  led  by  the  perusal 
of  Smeaton's  observations,  without  knowing  anything  of  the  previous 
labors  of  these  gentlemen  on  the  Continent,  or  of  Mr.  Frost,  the 
acknowledged  imitator  of  M.  Vicat  in  this  country." 

In  a  work  on  "Hydraulic  Mortars,"  published  at  Leipzig  in 
1869,  by  Dr.  Michaelis,  the  following  passage  occurs:  "A  century 
has  elapsed  since  the  celebrated  Smeaton  completed  the  building  of 
the  Eddystone  Lighthouse.  Not  only  to  sailors,  but  to  the  whole 
human  race  is  the  lighthouse  a  token  of  useful  work,  a  light  in  a  dark 
night. 

"  In  a  scientific  point  of  view,  it  has  illuminated  the  darkness  of 
almost  two  thousand  years.  The  errors  which  descended  to  us  from 
the  Romans,  and  which  were  made  by  such  an  excellent  author  as 
Belidor,  were  dispersed.  The  Eddystone  Lighthouse  is  the  founda- 
tion upon  which  our  knowledge  of  hydraulic  mortars  has  been  erected, 
and  it  is  the  chief  pillar  of  our  architecture. 

"  Smeaton  freed  us  from  the  fetters  of  tradition  by  showing  us  that 
the  purest  and  hardest  limestone  is  not  the  best,  at  least  for  hydraulic 
purposes,  and  that  the  cause  of  hydraulicity  must  be  sought  for  in 
"the  argillaceous  admixture. 


AMERICAN    CEMENTS.  13 

"  It  was  a  long  time  before  men  of  science  confirmed  this  state- 
ment of  the  English  engineer,  or  corrected  the  ideas  on  the  hardening 
of  hydraulic  mortars,  which  were  then  necessarily  confused  on  ac- 
count of  the  imperfect  state  of  chemistry  at  that  time.  How  could 
science  subsequently  keep  pace  with  practical  progress  ?  For  even  at 
present,  though  we  have  possessed  for  about  half  a  century  the  most 
excellent  hydraulic  mortars,  the  hardening  process  is  not  yet  com- 
pletely explained." 

These  extracts  from  eminent  authorities  on  hydraulic  cement  may 
be  taken  as  substantial  evidence  that  Smeaton  was  the  first,  not  to 
discover,  as  claimed  by  these  and  other  writers,  but  to  re-discover 
the  lost  art  of  cement  fabrication.  There  is  no  doubt  whatever  but 
that  the  ancients  thoroughly  understood  the  value  of  impure  lime- 
stones for  hydraulic  cementing  purposes. 

The  fact  is,  that  the  history  of  natural  rock  cement  reaches  so 
far  back  into  the  early  ages,  that  it  is  impossible  to  learn  precisely 
the  date  of  its  first  fabrication.  But  we  do  know  that  the  ancient 
Egyptians  made  natural  cement  four  thousand  years  ago  which  would 
set  and  harden  under  water.  The  Romans  over  two  thousand  years 
ago  made  most  excellent  natural  cement,  and  used  it  in  enormous 
quantities  for  sewers,  water  pipes,  bathing  fountains,  piers,  break- 
waters, aqueducts,  etc.  Prior  to  this  time,  an  aqueduct  over  seventy 
miles  in  length  was  built  at  the  ancient  city  of  Carthage.  At  one 
place  it  was  carried  across  a  valley  on  arches  over  one  hundred  feet 
high,  and  there  were  one  thousand  arches  in  line.  In  its  construction 
an  immense  quantity  of  natural  hydraulic  cement  was  used.  Some  of 
these  arches  are  still  standing.  At  one  point  where  the  arches  were 
highest  a  single  piece  over  one  hundred  feet  in  length  has  fallen  from 
the  top  down  upon  the  rocks  below.  It  still  lies  there  intact,  un- 
broken, an  excellent  illustration  of  the  toughness  and  tenacity  of 
natural  rock  cement. 

In  many  places  in  Mexico  and  Peru  natural  rock  cement  was  used 
so  long  ago  in  stone  masonry  that  the  stones  themselves  are  worn 
away,  leaving  the  cement  mortar  projecting  from  the  joints.  During 
the  winter  of  1892,  while  some  excavations  were  being  made  in  the 
city  of  London,  England,  for  railway  purposes,  the  workmen  came 
upon  a  heavy  mass  01  natural  cement  concrete  laid  over  eight  hundred 
years  ago. 


14:  AMERICAN    CEMENTS. 

Owing  to  the  proximity  of  buildings,  it  could  not  be  blasted  out, 
and  men  were  set  to  work  to  cut  it  out  with  chisels  and  hammers, 
and  the  concrete  was  so  hard  as  to  turn  the  best  steel  that  could  be 
obtained. 

Writers  on  the  subject  of  hydraulic  cements,  used  by  the  an- 
cients, and  especially  that  used  by  the  Romans,  have,  without  excep- 
tion, asserted  that  their  hydraulic  cement  was  made  by  a  mechanical 
mixture  of  fat  lime  and  pozzuolana. 

It  is  inconceivable  that  such  an  absurd  fallacy  could  obtain  and 
prevail  throughout  all  the  centuries  from  the  time  of  Vitruvius,  a 
Roman  architect  (who,  it  is  asserted,  served  as  a  military  engineer 
under  Caesar  and  Augustus),  down  to  the  time  of  Smeaton,  in  1756, 
and  still  more  absurd  that  it  should  be  handed  down  from  Smeaton's 
time  to  the  present  day  without  contradiction,  when  the  experiments 
made  by  Smeaton,  and  published  by  him,  utterly  contradict  such  a 
theory. 

G.  R.  Burnell,  C.  E.,  of  London,  in  his  work  on  ««  Limes, 
Cements,  and  Mortars,  1868,"  referring  to  Smeaton,  says:  "The 
results  he  arrived  at  were  very  remarkable,  not  only  for  their  practical 
utility,  but  also  as  an  illustration  of  the  ease  with  which  a  very  acute 
observer  may  stop 'short  on  this  side  of  the  attainment  of  a  great  truth. 
Smeaton  found  that  the  commonly  received  opinion  that  the  hardest 
stones  gave  the  best  limes  was  only  true  as  far  as  regarded  each  quality 
considered  by  itself.  That  is  to  say,  that  of  limes  not  fit  to  be  used 
as  water  cements,  those  made  of  the  hardest  stones  were  the  best 
for  certain  uses  in  the  air,  but  that,  whether  obtained  from  the 
hardest  marbles  or  the  softest  chalk,  such  limes  were  equally  useless 
when  employed  under  water.  He  found  that  all  the  limes  which 
could  set  under  water  were  obtained  from  the  calcination  of  such  lime- 
stones as  contained  a  large  portion  of  clay  in  their  composition. 

««  His  experiments  led  him  to  use  for  the  important  work  of  the 
lighthouse  a  cement  compounded  of  blue  lias  hydraulic  lime  from 
Aberthaw,  and  of  pozzuolana  brought  from  Civita  Vecchia,  near 
Rome. 

"  Even  at  the  present  day,  it  would  be  difficult  to  employ  a  better 
material  than  this,  excepting  that  the  price  would  insure  a  preference 
for  the  Roman  cement,  then  unknown." 


AMERICAN    CEMENTS.  15 

Smeaton,  in  his  ««  Narrative  of  the  Eddystone  Lighthouse,"  says: 
"  It  remains  a  curious  question  which  I  must  leave  to  the  learned 
naturalist  and  chemist,  why  an  intermediate  mixture  of  clay  in  the 
composition  of  limestone  of  any  kind,  either  hard  or  soft,  should 
render  it  capable  of  setting  in  water  in  a  manner  no  pure  lime  I  have 
yet  seen,  from  any  kind  of  stone  whatsoever,  has  been  capable  of 
doing.  It  is  easy  to  add  clay  in  any  proportion  to  a  pure  lime,  but  it 
produces  no  such  effect ;  it  is  easy  to  add  brick-dust,  either  finely  or 
coarsely  powdered,  to  such  lime  in  any  proportion  also  ;  but  this  seems 
unattended  with  any  other  effect  than  what  arises  from  other  bodies 
becoming  porous  and  spongy,  and  therefore  absorbent  of  water,  as 
already  hinted,  and  excepting  what  may  reasonably  be  attributed  to 
the  irony  particles  that  red  brick-dust  may  contain.  In  short,  I  have 
as  yet  found  no  treatment  of  pure  calcareous  lime  that  rendered  it 
more  fit  to  set  in  water  than  it  is  by  nature,  except  what  is  to  be 
derived  from  the  admixture  of  trass,  pozzuolana,  and  some  ferrugi- 
nous substance  of  a  similar  nature." 

It  would  seem  that  this  description  by  Smeaton,  as  to  the  action 
of  pure  limes,  coupled  with  his  discovery  as  to  the  hydraulicity  of 
impure  ones,  ought  to  have  annihilated  the  ancient  fallacy,  but  it  did 
not. 

Quoting  again  from  Burnell :  "  Some  curious  facts  might  be 
mentioned,  not  only  to  show  the  influence  of  a  large  body  of  masonry 
in  retarding  the  solidification  of  the  mortar  in  the  interior,  but  also  of 
the  danger  of  using  rich  limes  in  cases  where  such  masses  are  neces- 
sary. Amongst  them  we  may  mention  a  fact  cited  by  Gen.  Treus- 
sart,  who  had  occasion  to  demolish,  in  the  year  1822,  one  of  the 
bastions  erected  by  Vauban  in  the  citadel  of  Strasburg  in  the  year 
1666. 

"In  the  interior,  the  lime  after  these  156  years  was  found  to  be 
as  soft  as  though  it  were  the  first  day  on  which  it  had  been  laid. 
Dr.  John  mentions  that  in  demolishing  a  pillar  nine  feet  in  diameter, 
in  the  church  of  St.  Peter  at  Berlin,  which  had  been  erected  80 
years,  the  mortar  was  found  to  be  perfectly  soft  in  the  interior.  In 
both  cases  the  lime  used  had  been  prepared  from  pure  limestone." 

It  is  not  known  whether  these  lime  mortars  were  made  by  an 
admixture  of  sand,  burnt  clay,  trass,  or  pozzuolana  with  the  lime, 
but,  so  far  as  results  are  concerned,  they  would  have  been  the  same, 


16  AMERICAN    CEMENTS. 

for  nothing  is  more  certain  than  that  pure  lime,  with  or  without  ad- 
mixture of  any  one  or  all  of  the  materials  named,  cannot  be  induced 
to  harden  by  simple  mechanical  mixture  of  these  substances  whether 
in  air  or  water.  It  never  has  done  so  and  never  will.  If  fat  lime 
can  be  made  to  assume  an  hydraulic  character,  by  its  admixture  with 
pozzuolana,  why  did  Smeaton  seek  further?  He  had  the  rich  lime 
and  he  had  the  pozzuolana.  Why  did  he  not  use  them  if  he  believed 
in  the  tradition  that  had  been  handed  down  through  the  centuries,  — 
that  such  a  combination,  although  purely  mechanical,  would  harden 
under  water? 

If  he  believed  that  the  Romans  used  this  material  in  all  their 
wonderful  hydraulic  cement  constructions,  why  did  he  hesitate  for  a 
moment  even?  The  answer  is  plain.  Simply  because  he  tried  it  in 
every  conceivable  way,  as  he  himself  states,  and  found  it  was  not 
true,  that  such  a  mortar  would  harden  under  water.  That  is  why  he 
sought  further.  And  yet,  all  who  write  of  Smeaton,  on  the  subject 
of  his  great  discovery,  while  acknowledging  that  he  found  the  ancient 
theory  false,  insist  that  the  public  shall  deem  it  true. 

It  is  quite  true,  that  rich  lime,  or  even  hydraulic  lime,  takes  very 
kindly  to  burnt  and  powdered  clay,  pulverized  bricks,  trass,  or  pozzuo- 
lana, all  of  which  are  substantially  one  and  the  same  thing,  the  latter 
two,  however,  being  of  volcanic  origin.  No  one  of  them  contains 
inherent  hydraulic  qualities,  and  their  mechanical  incorporation  with 
rich  lime  can  in  no  manner  render  the  latter  hydraulic. 

Although  Smeaton  used  pozzuolana  with  the  Aberthaw  hydraulic 
lime  in  the  construction  of  the  Eddystone  Lighthouse,  yet  it  is  doubt- 
ful if  he  would  have  done  so  had  he  not  "  fortunately  found  at 
Plymouth  (where  he  was  cutting  and  fitting  the  stones  for  the  light- 
house) a  considerable  quantity  of  this  material  which  a  merchant  had 
imported  on  speculation,  expecting  to  sell  it  to  the  constructors  of  old 
Westminster  bridge." 

Henry  Reid,  in  his  work  on  "  Portland  Cement,"  London,  1877, 
states,  u  The  Aberthaw  lime  in  itself  could  have  accomplished  all  he" 
(Smeaton)  *«  desired,  for  he  had  unlocked  the  mystery  of  hydraulicity, 
and  felt  confident  in  the  knowledge  of  its  cause." 

The  composition  of  trass  and  pozzuolana  will  be  found  in  the 
table  of  analyses. 


AMERICAN    CEMENTS.  17 

Although  Smeaton  had  discovered  during  the  winter  of  1756-57 
that  certain  strata  in  the  blue  lias  formation  would,  after  calcination, 
produce  an  excellent  hydraulic  lime,  it  appears  that  he  only  made  use 
of  layers  containing  clay  in  such  proportion  as  to  cause  his  manu- 
factured lime  to  slake  by  hydration. 

It  is  very  probable  that  he  calcined  some  of  the  lower  layers, 
but,  finding  they  did  not  slake  readily,  confined  himself  to  the  use  of 
such  layers  as  would  do  so. 

The  idea  of  pulverizing  such  layers  as  would  not  slake  readily, 
then  testing  them,  and  forming  thereby  a  very  energetic  hydraulic 
cement,  did  not  occur  to  him  ;  and  this  is  probably  the  point  referred 
to  by  Burnell,  wherein  he  states,  as  already  quoted,  ««  An  illustration 
of  the  ease  with  which  a  very  acute  observer  may  stop  short  on  this 
side  of  the  attainment  of  a  great  truth." 

In  1786  De  Saussure  found  that  the  lime  of  Chamouni  set  under 
water,  and,  like  Smeaton,  attributed  this  faculty  to  the  presence  of  clay. 

Mr.  Parker,  of  London,  in  the  year  1796,  took  out  a  patent  for 
the  manufacture  of  what  he  called  "  Roman"  cement  from  the  sep- 
taria,  nodules  of  the  London  clay  formation  found  in  the  Isle  of 
Sheppy. 

This  septaria  was  natural  cement  rock,  and  after  calcination  it 
was  reduced  to  powder  in  mills  suited  to  the  purpose.  This  was 
undoubtedly  the  beginning  of  the  natural  rock  cement  industry  in 
modern  times.  Its  introduction  by  Parker  was  soon  followed  by  its 
manufacture  from  the  blue  lias  formation,  and  it  went  into  general  use 
throughout  England. 

Reid  says,  in  speaking  of  Parker's  Roman  cement,  ««  The  Thames 
tunnel  could  not  have  been  made  but  for  the  advantages  it  secured, 
and  many  of  the  early  railway  tunnels  were  built  with  it  as  a  cementing 
agent." 

Burnell,  as  late  as  1868,  in  his  work  on  "  Limes  and  Mortars," 
states  in  regard  to  Roman  cement,  "  Almost  all  of  the  works  executed 
in  water  in  England  at  the  present  day  are  executed  with  it." 

In  1802  natural  cement  was  produced  at  Boulogne,  France. 
The  rock  at  Boulogne  is  in  the  form  of  septaria,  and  is  sometimes 
called  "  Boulogne  pebbles."  Its  proportions  of  clay  and  carbonate  of 
lime  are  such  that  it  is  used  for  the  production  of  natural  Portland 
cement. 


18  AMERICAN    CEMENTS. 

In  1 8 10  Edgar  Dobbs,  of  South wark,  London,  obtained  a  patent 
for  the  manufacture  of  artificial  hydraulic  lime  or  cement,  by  mixing 
together  in  suitable  proportions  carbonate  of  lime  and  clay,  and  after 
drying,  he  moulded  or  cut  it  into  pieces  before  burning.  He  then 
states  that  "the  burning  must  be  sufficient  to  expel  the  carbonic  acid 
from  the  lime  without  vitrifying  any  of  the  substances.*' 

This  is  the  first  record  we  have  of  the  production  of  artificial 
cement,  or,  as  it  was  then  called,  "  artificial  hydraulic  lime." 

From  1813  to  1818  the  artificial  hydraulic  limes  were  produced 
in  France  by  M.  Vicat,  and  by  Dr.  John  of  Berlin,  and  Raucourt  de 
Charleville  in  Russia. 

In  1824  one  Joseph  Aspdin,  of  Leeds,  England,  obtained  a  patent 
for  the  manufacture  of  an  artificial  cement  which,  in  his  specifications, 
he  designated  as  "  Portland  cement." 

This  being  the  first  time  the  word  "  Portland  "  was  ever  coupled 
with,  or  in  any  way  mentioned  in  connection  with  cement,  whether 
natural  or  artificial,  there  is  no  doubt  whatever  that  Mr.  Aspdin  is 
entitled  to  the  doubtful  distinction  of  inventing  the  term,  for  certainly 
it  is  a  most  absurd  and  meaningless  word  so  far  as  it  relates  to  hy- 
draulic cement. 

Mr.  Parker,  on  the  other  hand,  had  ample  justification  for  naming 
his  product  ««  Roman  cement,"  for  he  had  but  reproduced  a  cement 
substantially  identical  to  that  used  by  the  Romans  1800  years  before, 
and  it  is  to  be  deeply  regretted  that  the  title  he  then  employed  did  not 
thereafter  cling  to  the  natural  rock  cements  the  world  over. 

In  the  year  1818,  twenty-two  years  after  Parker  had  patented 
his  Roman  cement,  Canvass  White  of  this  country  discovered  and 
patented  a  similar  cement  found  at  or  near  Fayetteville,  N.  Y. 

This  cement  was  used  in  large  quantities  in  the  construction  of 
locks,  viaducts,  and  culverts  on  the  Erie  Canal,  at  that  time  in  the 
course  of  construction.  Subsequently  the  State  of  New  York  pur- 
chased the  patent  from  Mr.  White,  paying  him  therefor  the  sum  of 
$10,000,  and  made  the  discovery  public  property. 

In  1824,  the  year  in  which  Aspdin  obtained  a  patent  on  his  arti- 
ficial Portland  cement,  natural  cement  rock  was  discovered  at  Williams- 
ville,  Erie  County,  N.  Y.,  where  a  manufactory  was  established. 
This  cement  was  used  extensively  in  the  construction  of  the  locks  on 
the  Erie  Canal  at  Lockport,  N.  Y. 


AMERICAN    CEMENTS.  19 

In  1826  natural  rock  cement  was  produced  at  Kensington,  Conn., 
and  was  continued  for  several  years,  the  production  amounting  to 
about  five  hundred  tons  yearly.  On  account  of  unfavorable  transpor- 
tation facilities,  the  production  ceased  soon  after  the  cements  manu- 
factured on  the  Hudson  River  were  placed  in  the  larger  markets. 

In  1828  a  cement  works  was  established  at  Rosendale,  Ulster 
County,  N.  Y.  The  product  of  the  factory  was  first  used  in  the 
construction  of  the  Delaware  and  Hudson  Canal,  then  being  built 
through  the  town  of  Rosendale. 

Other  cement  works  soon  followed  at  this  place.  Owing  to  the 
general  good  quality  of  the  cement  rock,  and  its  proximity  to  New 
York  City,  as  well  as  the  advantages  afforded  by  cheap  transportation 
on  the  Hudson  River,  this  locality  rapidly  developed  into  the  leading 
natural  rock  cement  center  of  this  country,  a  position  it  maintains  to 
the  present  day.  Its  yearly  production  amounts  to  about  two  and 
three  fourths  million  barrels. 

In  the  year  1829  cement  rock  was  discovered  at  Louisville, 
Ky.,  while  excavations  were  being  made  for  the  Louisville  and  Port- 
land Canal,  and  it  was  manufactured  and  used  during  that  year 
in  the  canal  walls  and  locks. 

Here  again  the  rock  proved  to  be  of  excellent  quality.  This 
fact,  taken  in  connection  with  the  conveniences  in  the  matter  of  trans- 
portation on  the  Ohio  River,  and  the  advantages  resulting  from  a  wide 
and  uncontested  field  of  trade,  led  to  the  rapid  introduction  of  this 
cement,  and  made  the  locality  the  center  of  the  cement  industry  be- 
yond the  Alleghenies,  and  in  some  seasons  the  production  has  been 
as  great  as  one  and  three  fourths  million  barrels,  and  is  exceeded  only 
by  the  production  from  the  Rosendale  district. 

During  the  summer  of  1831  excavations  were  made  for  a  canal  on 
the  left  bank  of  the  Susquehanna  River  to  connect  Muncy  and  Lock 
Haven,  Penn.,  at  a  point  about  ten  miles  west  of  Williamsport  on  land 
known  then  and  now  as  "King's  Farm."  The  excavations  disclosed 
an  enormous  body  of  rock, -which  was  ascertained  by  Mr.  Robert 
Farries,  chief  engineer  of  the  canal,  to  be  hydraulic  cement  rock. 
Col.  George  Crane,  a  prominent  man  of  his  time,  living  in  a  stately 
stone  mansion  across  the  river  directly  opposite  "  King's  Farm,"  was 
a  contractor  on  the  canal  at  the  time,  and  at  once  set  about  con- 
structing a  cement  works  for  the  manufacture  of  cement  from  this 


20  AMERICAN    CEMENTS. 

deposit  for  use  in  the  construction  of  the  canal.  He  built  five  kilns 
with  suitable  facilities  for  grinding,  and  his  cement  was  used  in  the 
construction  of  the  locks,  bridges,  culverts,  dams,  and  viaducts,  the 
latter,  in  some  places,  being  over  three  hundred  feet  in  length. 

When  the  canal  was  finished  in  1834,  the  manufacture  of  the 
cement  was  discontinued,  but  the  condition  of  the  work  done  over 
sixty  years  ago  with  the  product  of  this  somewhat  primitive  plant 
gives  promise  to-day  that  the  rocks  themselves  will  endure  no  longer 
than  the  material  which  binds  them  together. 

In  1836  the  Cumberland  Hydraulic  Cement  and  Manufacturing 
Company  established  a  natural  rock  cement  works  at  Cumberland, 
Md.,  which  has  since  been  in  continuous  and  successful  opera- 
tion. As  a  result  of  the  excellent  quality  of  this  rock,  other  works 
were  subsequently  erected,  and  the  yearly  output  has  been  large,  and 
Cumberland  cement  bears  a  most  excellent  reputation. 

In  1837  cement  rock  was  discovered  at  Round  Top  on  the  left 
bank  of  the  Potomac  River,  near  Hancock,  Md.,  by  A.  B.  Mc- 
Farlan,  a  contractor  of  Washington,  D.  C.,  who  manufactured 
cement  from  this  rock  in  the  following  year,  and  used  it  in  the  con- 
struction of  the  Chesapeake  and  Ohio  Canal.  The  graceful  viaducts 
along  the  line  of  this  canal,  with  the  mortar  unimpaired,  attest  the 
enduring  qualities  of  Round  Top  cement. 

It  was  during  1838  that  cement  rock  was  discovered  at  Utica, 
111.,  and  works  were  erected  during  that  year  by  Norton  &  Steele 
to  supply  cement  for  the  construction  of  the  locks,  culverts,  and 
bridges  of  the  Illinois  and  Michigan  Canal,  and  the  rock  proving  to 
be  of  most  excellent  quality,  the  manufacture,  since  that  time,  has  been 
uninterrupted. 

In  1845  this  plant  passed  into  the  possession  of  Mr.  James 
Clark  of  Utica,  111.,  and  was  operated  by  him  until  1888,  at  which 
time  it  was  incorporated  as  the  Utica  Hydraulic  Cement  Company, 
and  its  capacity  largely  increased.  This  cement  has  always  stood 
well  in  public  favor.  In  the  masonry  laid  with  it  over  fifty-five  y 
ago,  the  joints  are  as  hard  to-day  as  the  stone  itself. 

In  1839  natural  rock  cement  was  first  produced  at  Akron, 
N.  Y.  The  rock  proving  of  exceptionally  fine  quality,  its  manufacture 
has  been  continuous,  and  steadily  increasing  in  volume.  Some  of 
the  most  important  engineering  works  of  the  country  have  been  con- 
structed with  it,  and  its  enduring  character  is  well  established. 


AMERICAN    CEMENTS.  21 

In  1848  cement  works  were  established  at  Balcony  Falls,  Va., 
by  H.  O.  Locher,  and  are  known  as  the  James  River  Cement  Works. 
H.  O.  Locher  £  Co.  are  still  the  proprietors  at  Holcomb's  Rock,  Va. 
The  cement  from  these  works  has  always  borne  an  excellent  repu- 
tation. 

In  1850  cement  rock  was  found  at  Siegfried's  Bridge  in  the  Le- 
high  Valley,  Penn.,  and  cement  was  produced  and  used  in  the  con- 
struction of  the  Lehigh  Coal  and  Navigation  Company  Canal  from 
Easton  to  Mauch  Chunk.  Its  manufacture  in  the  Lehigh  Valley  has 
been  continuous,  and  has  assumed  large  proportions,  with  a  con- 
stantly increasing  demand. 

In  1850  cement  rock  was  discovered  at  Cement,  Ga.,  by 
Rev.  Chas.  W.  Howard  of  Charleston,  S.  C.,  and  the  eminent 
chemist,  St.  Julien  Ravenel,  also  of  Charleston  (and  a  personal 
friend  of  Prof.  Agassiz),  who  analyzed  the  rock,  found  it  to  be  of 
a  high  grade  ;  and  its  manufacture  was  commenced  by  Mr.  Howard 
and  his  son  in  the  following  year,  and  was  prosecuted  by  them  until 
the  beginning  of  the  late  war,  when  they  both  volunteered  in  the  Con- 
federate service,  and  the  cement  factory  was  allowed  to  fall  into 
disuse. 

In  1867  Col.  George  H.  Waring,  then  of  Savannah,  Ga., 
purchased  the  property,  and  again  the  plant  was  put  in  running  con- 
dition, and  has  since  been  operated  continuously  as  the  Howard 
Hydraulic  Cement  Company,  Geo.  H.  Waring,  president. 

The  cement  manufactured  by  this  company  probably  has  no 
superior  in  this  or  any  other  country.  Used  as  an  exterior  plaster  in 
1852  by  Dr.  Ravenel  on  his  house  in  Charleston,  situated  on  the 
Battery,  where  the  walls  are  exposed  to  the  disintegrating  influences  of 
salt  spray,  the  stucco  still  remains  unimpaired,  while  the  sandstone 
lintels  of  the  windows  have  long  since  been  worn  away. 

In  1867  hydraulic  cement  rock  was  first  discovered  at  Fort 
Scott,  Kan.,  and  its  manufacture  was  commenced  in  the  following 
ye£r,  and  since  that  time  has  been  continued  uninterruptedly,  the 
\y#rks  having,  for  several  years,  been  controlled  and  operated  by  The 
C.  A.  Brockett  Cement  Company,  of  Kansas  City,  Mo.  This 
company  has  some  local  advantages  not  enjoyed  by  others.  An  ex- 
cellent vein  of  coal  underlies  the  cement  rock,  being  separated  from  it 
by  a  stratum  of  fine  fire  clay.  This  coal  is  used  in  the  manufacture  of 


22  AMERICAN    CEMENTS. 

the  cement,    which  in  its   general   characteristics   greatly  resembles 
that  of  Cement,  Ga. 

In  1869  the  manufacture  of  natural  rock  cement  was  established 
at  La  Salle,  111.,  on  the  line  of  the  same  cement  rock  formation 
running  through  Utica,  111.,  and  has  since  been  in  continuous  and 
successful  operation. 

In  1870  a  cement  works  was  established  at  Howe's  Cave,  N.  Y., 
and  has  been  operated  continuously  since  then,  producing  a  cement 
of  uniformly  good  quality,  which  has  been  used  successfully  in  many 
very  important  public  buildings  and  heavy  masonry. 

In  1874  the  Buffalo  Cement  Company  commenced  the  manufacture 
of  natural  rock  cement  at  Buffalo,  N.  Y.,  and  owing  to  the  ex- 
cellent quality  of  the  cement  rock,  the  manufactured  product  rapidly 
advanced  in  public  favor. 

In  1877  the  works  were  rebuilt  on  a  large  scale,  and  the  capacity 
greatly  increased.  With  almost  unequalled  facilities  for  transporta- 
tion, this  company  has  been  very  successful ,  and  now  enjoys  a  large 
and  increasing  trade. 

In  1875  the  Milwaukee  Cement  Company  entered  upon  the 
manufacture  of  natural  rock  cement  near  Milwaukee,  Wis.  The  suc- 
cess of  this  company  has  been  phenomenal.  With  rock  of  a  uniform 
and  reliable  character,  and  with  works  equal,  if  not  superior,  to 
any  in  the  country,  and  with  splendid  transportation  facilities,  this 
cement  has  gained  an  enviable  position  in  the  markets  of  the  West. 

In  1883  a  large  plant  for  the  manufacture  of  natural  rock  cement 
was  established  at  Mankato,  Minn.  The  works  are  of  stone,  and 
present  a  fine  and  substantial  appearance.  The  cement  rock  is  of  the 
very  best  quality,  and  the  manufactured  product  has  obtained  a  strong 
foothold  in  the  markets  of  the  Northwest.  Mortar  made  from  this 
cement  becomes  exceedingly  hard  and  stone-like  in  character,  whether 
above  or  below  water,  and  withstands  to  a  remarkable  degree  the 
disintegrating  effects  of  alternate  freezing  and  thawing. 

In  closing  this  brief  and  incomplete  resumb  of  the  rock  cement 
industry  in  this  and  foreign  lands,  it  may  be  well  to  emphasize  the 
fact  that  in  no  other  country  of  the  world  is  there  to  be  found  cement 
rock  formations  which  are  at  all  to  be  compared  with  those  so  well 
distributed  throughout  the  United  States. 


AMERICAN    CEMENTS.  23 

The  principal  source  of  rock  cements  in  England  is  from  the 
Liassic  or  upper  and  lower  Blue  Lias  subdivision  of  the  Jurassic  rock 
formation,  extending  from  Lyme  Regis  on  the  south  coast  in  a  northerly 
direction  to  Yorkshire  on  the  north,  and  averaging  some  thirty  miles 
in  width. 

From  the  Memoirs  of  the  geological  survey  of  the  Jurassic  rocks 
of  Britain,  and  more  especially  the  report  on  the  Lias  of  England  and 
Wales,  by  Horace  B.  Woodward,  London,  1893,  we  glean  certain 
facts  regarding  bed  formations  and  the  source  of  the  Roman  or  rock 
cement  supply  in  that  country  since  the  days  of  Parker  to  the  present 
time,  from  which  we  can  readily  understand  why  the  artificial  produc- 
tion of  cement  was  resorted  to. 

The  Lower  Lias,  from  which  the  rock  cements  are  obtained,  con- 
sists in  its  lower  portion  of  layers  of  blue  and  gray  limestones,  more 
or  less  argillaceous.  These  layers  occur  sometimes  in  even  and 
sometimes  in  irregular  bands,  often  nodular  and  interrupted,  and  they 
alternate  with  blue  and  brown  marls,  clays,  and  shales.  Nowhere  in 
the  Lower  Lias  is  there  any  marked  band  of  rock  which  can  be  traced 
continuously  for  any  great  distance.  The  higher  portion  of  the  Lower 
Lias  consists  of  blue,  more  or  less  micaceous  clays,  shales,  and  marls, 
with  occasional  septaria  nodules  and  bands  of  earthy  and  shelly  lime- 
stones and  sandy  layers.  There  is  no  rigid  plane  of  demarcation  be- 
tween them  and  the  mass  of  limestones  beneath,  while  the  clays  pass 
upward  into  the  lower  beds  of  the  Middle  Lias  with  no  lithological 
break  or  divisional  line. 

There  is  no  layer  of  the  rock  used  for  cement  purposes  which 
does  not  vary  in  its  proportion  of  clay,  ofttimes  as  much  as  twenty 
per  cent  in  individual  quarries ;  and  we  find  that  whereas  one  layer 
may  contain  eight  per  cent,  the  one  next  above  or  below  may  contain 
fifty  per  cent  of  clay. 

Clearly  it  is  not  remarkable  that  a  cement  made  from  such  an  ill- 
assorted  mass  of  material  should  lack  uniformity.  No  rational  man 
in  America  would  dream  of  undertaking  to  produce  a  rock  cement 
from  such  a  jumble  of  clays,  shales,  marls,  nodules,  limestones,  and 
cement  stones.  Is  it  then  to  be  wondered  at  that  artificial  mixtures 
were  employed  in  an  endeavor  to  meet  and  overcome  the  dissatisfac- 
tion unavoidably  growing  out  of  the  use  of  such  natural  rock  cements  ? 


24  AMERICAN    CEMENTS. 

Contrast  these  materials  with  our  own  massive  cement  rock  de- 
posits !  Here  we  have  immense  beds  of  cement  rock  absolutely  free 
from  any  extraneous  substances,  perfectly  pure  and  clean,  with  layer 
upon  layer,  extending  for  thousands  of  feet,  without  an  appreciable 
variation  in  the  proportion  of  ingredients. 

Cement  rock  quarries  are  worked  in  this  country  decade  after 
decade  without  the  necessity  of  discarding  a  pound  of  the  material, 
and  analyses  taken  during  successive  years  show  no  marked  changes 
in  the  constituent  parts.  Had  England  possessed  such  cement  rock 
formations  as  are  distributed  throughout  this  country,  it  is  extremely 
doubtful  if  the  production  of  artificial  cement  would  have  been  re- 
sorted to.  Under  such  circumstances  there  would  have  been  no 
occasion  for  it. 

The  magnitude  and  value  of  the  work  done  with  the  rock  cements 
of  this  country  is  almost  beyond  comprehension.  They  have  been 
used  in  the  largest  buildings,  tunnels,  bridges,  dams,  and  aqueducts 
constructed  in  America,  and  a  failure  has  yet  to  be  reported  and  re- 
corded. More  than  seventy-seven  million  barrels  have  been  so  used 
during  the  past  twelve  years. 

In  subsequent  chapters  the  various  rock  cement  deposits  of  this 
country  will  be  discussed  in  detail,  with  descriptions  of  the  various 
plants,  together  with  a  mention  of  the  important  works  executed  with 
the  various  brands,  the  magnitude  and  permanence  of  which  should  set 
at  rest  all  question  and  all  doubts  concerning  the  enduring  qualities  of 
American  rock  cements. 


AMERICAN    CEMENTS.  25 


CHAPTER    II. 


COMMON  QUICKLIME  —  SLIGHTLY  HYDRAULIC  LIME  —  EMINENTLY 
HYDRAULIC  LIME  —  HYDRAULIC  CEMENTS  —  HINTS  AS  TO 
METHODS  OF  CEMENT  ROCK  CALCINATION. 

Nature  has  supplied  this  country  with  practically  inexhaustible 
deposits  of  hydraulic  limestones,  and  in  almost  endless  variety  of  com- 
binations. 

In  order  to  classify  these  varieties  and  reach  intelligent  conclu- 
sions concerning  them,  the  following  arrangement  considered  subse- 
quent to  calcination  has  been  employed  as  fairly  representative  : — 

1.  Common  quicklime. 

2.  Slightly  hydraulic  lime. 

3.  Eminently  hydraulic  lime. 

4.  Hydraulic  cements. 

The  deposits  from  which  all  or  nearly  all  of  these  classes  may  be 
obtained  occur  in  nearly  every  State  and  Territory  of  the  United 
States. 

It  is  the  presence  of  clay  in  greater  or  less  proportions  in  these 
limestones  which  confers  upon  them  their  hydraulicity,  or  power  to 
set  and  harden  either  in  air  or  water. 

The  greater  the  proportion  of  clay  in  a  limestone,  up  to  a  certain 
fixed  limit,  the  greater  will  be  its  hydraulic  activity. 

COMMON     QUICKLIME. 

Pure  lime  of  itself  contains  no  setting  properties  whatever.  It  is 
a  base  which,  if  combined  with  an  acid,  like  silica,  loses  its  caustic 
properties,  and  takes  a  new  form  known  as  silicate  of  lime. 

The  latter,  if  composed  of  correct  combining  proportions,  will, 
upon  the  application  of  water,  commence  to  crystallize  and  harden, 
whether  in  air  or  water,  and  without  an  appreciable  development  of 
heat. 

Pure  lime  alone  when  subjected  to  water  will,  in   the  process  of 


26  AMERICAN    CEMENTS. 

hydration,  develop  heat  as  high  as  300°  F.,  but  it  will  not  crystallize,  as 
has  been  stated  so  often  by  eminent  writers. 

That  pure  limestone  occurs  in  massive  crystalline  form  is  due  to 
its  chemical  combination  with  carbonic  acid.  It  will  also  crystallize 
when  combined  with  sulphuric  acid,  as  in  calcined  gypsum,  or  plaster 
of  Paris. 

But  with  water  alone,  it  will  not  crystallize.  Mortars  made  from 
pure  lime  and  sand  will  attain  a  certain  degree  of  hardness  when  used 
above  ground,  due  mostly  to  the  process  of  drying  out,  and  possibly 
a  slight  amount  of  reabsorption  of  carbonic  acid. 

This  process  is  so  slow,  however,  as  to  be  inappreciable  during 
an  ordinary  lifetime. 

This  is  easily  proven  by  placing  in  water  a  sample  of  the  oldest 
lime  mortar  to  be  found.  If  the  lime  is  approximately  pure,  the  mor- 
tar will  in  a  few  days  crumble  into  mud,  and  the  lime  will  be  taken 
up  in  solution  in  the  water,  and  if  the  water  is  changed  frequently  the 
lime  will  entirely  disappear,  leaving  the  sand  as  clean  as  when  in  its 
native  bed. 

SLIGHTLY   HYDRAULIC    LIME. 

Lime  that  contains  sufficient  clay  to  enable  it  to  be  classed  as 
slightly  hydraulic  lime  will  contain  ten  to  twelve  per  cent  of  clay.  This 
amount  of  impurities  will  not  prevent  the  lime  from  slaking,  although 
it  will  slake  more  slowly  than  will  a  lime  which  is  pure  or  nearly  pure. 

It  will  not  appear  as  white  as  the  latter,  neither  will  it  develop  so 
high  a  degree  of  heat  during  hydration;  but  as  a  mortar-making 
material  for  brick  or  stone  masonry  it  is  vastly  superior  to  that  of 
pure  lime,  as  it  contains  inherent  setting  and  hardening  properties 
amounting  —  with  the  proportion  of  clay  mentioned — to  about  thirty 
per  cent  of  silicates  or  active  setting  matter,  i.  e.,  hydraulic  cement. 

Such  a  lime,  when  made  into  mortar  with  the  requisite  amount 
of  sand,  will  cement  properly  moistened  bricks  so  firmly  together  that 
in  a  few  years  the  bricks,  rather  than  the  mortar,  will  be  disrupted 
when  subjected  to  tensile  strain. 

EMINENTLY    HYDRAULIC    LIME. 

A  lime  in  which  clay  is  present  to  the  extent  of  eighteen  to 
twenty-two  per  cent  is  classed  as  an  eminently  hydraulic  lime.  Con- 


AMERICAN    CEMENTS.  27 

taining  about  fifty  per  cent  of  hydraulic  cement,  it  will,  when  properly 
calcined,  reduced  to  powder,  hydrated,  and  thoroughly  mixed  with 
sand,  produce  a  mortar  that,  for  enduring  qualities,  when  exposed  to 
the  atmosphere,  is  superior  to  any  known  mortar-making  material. 

It  is  sufficiently  hydraulic  to  be  classed  as  a  very  slow-setting 
hydraulic  cement. 

Concrete  made  from  such  a  mortar  will  require  from  sixty  to 
ninety  days  to  become  sufficiently  hardened  to  bear  submersion. 

This  quality  of  lime  has  been  used  extensively  in  Europe  for 
many  years  in  the  making  of  concrete  blocks  for  sea-walls  and  general 
submarine  masonry, —  notably  in  France  during  the  past  sixty  years. 

Beckwith  states  that  the  hydraulic  limestone  quarries  of  Teil, 
France,  have  been  worked  for  several  centuries. 

John  Smeaton,  C.  E.,  of  England,  used  an  eminently  hydraulic 
lime  mortar  in  the  construction  of  the  Eddystone  Lighthouse,  in  1757. 

There  are  tens  of  millions  of  tons  of  this  class  of  hydraulic  lime- 
stone in  this  country,  which  can  be  produced  at  a  low  cost  and  will  be 
so  produced,  whenever  our  engineers  and  architects  create  a  demand 
for  it. 

HYDRAULIC    CEMENTS. 

A  limestone  which,  after  calcination,  is  proven  by  analysis  to  con- 
tain thirty-eight  to  forty-two  per  cent  of  clay  will  produce  an  active- 
setting  hydraulic  cement. 

Upward  of  one  hundred  and  forty  million  barrels  of  this  class  of 
cements  have  been  produced  and  consumed  in  the  United  States  since 
its  first  production,  in  1818. 

During  the  last  ten  years  ending  Jan.  I,  1895,  the  production  was 
66,255,682  barrels. 

•  Fully  ninety-five  per  cent  of  all  the  great  engineering  and  archi- 
tectural work  of  this  country  has  been  done  with  this  class  of  Ameri- 
can rock  cements. 

The  failures  to  do  excellent  work  will  not  aggregate  one  hun- 
dredth of  one  per  cent. 

Probably  no  country  on  the  globe  is  more  favored  with  such  an 
abundance,  and  of  such  excellent  quality,  of  natural  cement  rock,  as  is 
known  to  exist  in  a  vast  number  of  localities  in  this  country. 


28  AMERICAN    CEMENTS. 

In  a  few  localities  in  France  there  are  natural  rock  cement  beds 
of  first  quality,  but  in  England  they  occur  very  rarely. 

In  our  classification  of  the  impure  limestones  of  the  United  States, 
we  have  defined  the  proportions  of  clay  within  certain  narrow  limits  for 
the  sake  of  a  starting  point,  but  the  proportions  of  clay  and  lime  vary 
in  different  localities,  and  the  action  of  these  ingredients  is  largely 
dependent  on  the  proportions  of  the  constituent  parts  of  the  clay, 
also  when  magnesia,  to  a  greater  or  less  extent,  enters  into  the  combi- 
nation, all  of  which  has  an  important  bearing  on  the  enduring  quali- 
ties of  a  cement. 

In  nearly  all  natural  cement  rock  formations,  in  all  countries,  it 
is  found  that  the  deposits  consist  of  several  layers  or  strata,  and  there 
is  usually  a  slight  variation  in  the  proportion  of  ingredients  as  between 
the  various  layers. 

As  a  rule  the  lower  strata  contain  the  greater  proportion  of  clay, 
which  gradually  diminishes  as  we  ascend  in  the  series  of  layers. 

All  manufacturers  of  natural  rock  cement  in  this  country  fully 
appreciate  the  advantages  to  be  gained  by  a  thorough  admixture  of 
the  several  layers. 

Whenever  it  is  found  that  there  is  a  considerable  variation  in  the 
proportions  of  the  clay  and  the  carbonates,  as  between  the  upper  and 
lower  layers,  and  these  are  mixed  together  and  subjected  to  calcina- 
tion in  the  same  kiln,  it  will  follow,  that  with  heat  sufficient  to  expel 
the  carbon  dioxide  from  the  upper  layers,  the  lower  ones  will  suffer 
somewhat  from  over-calcination,  producing  a  variable  quantity  of  light 
and  friable  clinker  that  has  to  be  excluded  as  waste,  being  devoid  of 
hydraulic  energy. 

By  the  calcination  of  the  lower  layers  separately,  and  at  such  a 
temperature  as  will  insure  the  leaving  of  one  or  two  per  cent  of  car- 
bon dioxide  in  the  product,  and  subsequently  mixing  this  product 
thoroughly  in  the  grinding  with  the  upper  layers  of  the  series  that 
shall  have  been  calcined  at  a  much  higher  temperature,  a  very  percep- 
tible improvement  in  the  quality  of  the  resultant  cement  is  sure  to 
follow,  and  the  loss  due  to  waste  clinker  will  be  obviated. 

Fortunately  the  occasions  for  this  precaution  are  exceedingly  rare 
in  this  country ;  indeed,  as  a  rule,  the  layers  are  so  evenly  balanced 
throughout  that  separate  calcination  is  not  practised,  and  the  amount 
of  loss  by  waste  clinker  is  so  slight  as  scarcely  to  be  considered. 


AMERICAN    CEMENTS.  29 

It  remains  true,  however,  that  this  matter  of  separate  calcination, 
although  it  may  at  present  seem  trivial,  will  ultimately  come  into  gen- 
eral practice  with  those  manufacturers  whose  great  ambition  is  to  pro- 
duce as  nearly  as  possible  a  perfect  cement,  without  regard  to  a  slight 
advance  in  cost. 

And  in  the  present  advanced  state  of  the  art,  it  is  certainly  along 
the  lines  indicated,  namely,  a  classification  and  separation  of  the 
various  layers  into  groups,  and  each  group  to  be  separately  calcined 
at  such  temperature  as  will  insure  the  best  results,  that  any  notable 
improvement  in  the  quality  of  our  American  rock  cements  need  be 
expected. 


30  AMERICAN    CEMENTS. 


CHAPTER   III. 

SILICATES  —  THE  EFFECT  OF  AN   EXCESS  OF  ALUMINA,  OF  MAG- 
NESIA, OF  FREE  LIME  —  ALKALIES  —  CHEMICAL  COMBINATIONS. 

There  are  two  distinct  classes  of  rock  cements  in  this  country, 
although  they  are  not  distinguishable  except  by  analysis. 

The  ordinary  consumer  will  never  note  the  difference,  as  the 
action  of  both  classes  is  the  same  under  like  circumstances. 

They  are  classified  as  double  (bi)  and  triple  (tri)  silicates,  and 
their  compositions  are  known  as 

1.  Silicate  of  lime  and  alumina. 

2.  Silicate  of  lime,  magnesia,  and  alumina. 

The  combining  proportions  of  these  silicates  differ  materially,  as 
the  former  requires  a  greater  percentage  of  silica  than  does  the  latter. 

During  the  year  1894  the  production  of  American  rock  cements 
amounted  to  7,595,676  barrels,  and  the  proportions  of  the  two  classes 
were  as  follows  :  — 

1.  Bisilicates         .         .         .'        .         .         2,557,464  barrels. 

2.  Trisilicates        .         .  .         .         5,038,212       «« 

Total        .         .         .         .      '   .         7,595,676       •« 
The  percentages  are  approximately  as  follows  :  — 

1.  Bisilicates  33-67  7 

2.  Trisilicates          66.33 ) 

Although  the  terms  "double"  and  "  triple  "  silicates  are  used  to 
distinguish  the  two  classes,  it  is  not  intended  that  the  rule  is  at  all 
absolute. 

On  the  contrary,  it  is  wellnigh  impossible  to  find  a  cement  which 
can  rightfully  be  classed  as  a  double  silicate  that  does  not  contain  a 
small  percentage  of  triple,  and  oftentimes  a  large  percentage  of  single, 
silicates;  therefore,  the  position  of  a  cement  in  this  classification  is  de- 
termined by  the  particular  form  of  silicates  which  in  its  composition 
predominates. 

So  tar  as  durability  and  general   excellence  are  concerned,   no 


AMERICAN    CEMENTS.  31 

distinction  can  be  drawn  between  these  two  classes  of  cements. 
They  have  been  produced  in  this  country  for  many  years,  the 
former  since  1818,  and  the  latter  since  1824.  The  durability  of 
either  depends  not  as  to  whether  it  be  a  double  or  triple  silicate,  but 
rather  upon  the  nearness  with  which  it  approaches  true  combining 
proportions.  Whichever  approximates  this  standard  closest  is, 
theoretically  at  least,  the  better  cement ;  but,  practically,  it  has  been 
demonstrated  by  long-continued  use  that  there  may  be  an  excess  of 
the  two  bases,  lime  and  magnesia,  without  detriment  to  the  enduring 
qualities  of  the  cements  whether  used  in  air  or  water. 

A  cement  containing  an  excess  of  alumina  will,  when  used  below 
ground  or  in  fresh  water,  remain  stable  and  firm  for  an  indefinite 
period,  but  is  apt  to  disintegrate  in  masonry  exposed  to  the  atmos- 
phere in  a  cold  climate.  Fortunately  the  rock  cements  of  this 
country  are  not  open  to  this  objection,  except  to  a  very  limited 
extent,  as  less  than  two  per  cent  of  the  total  output  can  fairly  be  so 
rated. 

It  is  often  stated  by  writers,  especially  those  who  advocate 
artificial  or  so-called  Portland  cements,  that  the  rules  governing 
chemically  combining  proportions  must  be  strictly  adhered  to ;  that 
an  excess  of  lime  is  not  only  objectionable,  but  positively  dangerous. 

If  this  be  true,  how  are  we  to  reconcile  ourselves  to  its  accept- 
ance, while  we  have  before  us  the  unquestioned  fact,  that  the  natural 
rock  hydraulic  limes  of  France  have  been  in  use  hundreds  of  years 
before  Portland  cement  came  into  existence,  and  are  in  use  to  this  day 
in  vastly  increasing  quantities  in  sea  water,  in  earth  foundations,  in 
masonry  exposed  to  the  atmosphere,  in  concrete  blocks  and  arches,  in 
monoliths,  and  in  important  works  of  every  kind,  and  yet  they  con- 
tain not  less  than  forty  per  cent  of  free  lime  ? 

Evidently  there  is  a  mistake  somewhere;  but  rather  than  question 
unduly,  hastily,  or  without  apparent  reason,  the  wisdom  of  so  many 
of  the  eminent  scientists  who  have  persisted  in  this  somewhat  arbi- 
trary view  ot  the  subject,  we  prefer  to  state  such  facts  as  are  within  the 
experience  of  those  familiar  with  the  use  of  cement,  and  at  the  same 
time,  by  quoting  liberally  from  the  works  and  statements  of  leading 
authorities,  make  clearly  evident  that  the  doctrine  so  maintained  is 
without  sound  foundation.  No  cement,  be  it  either  natural  rock  or 
Portland,  contains  ingredients  in  exact  combining  proportions.  There 


32  AMERICAN    CEMENTS. 

is  usually  a  slight  variation.  Some  contain  an  excess  of  clay,  and 
others  an  excess  of  lime  or  magnesia.  These  variations  are  not  so 
great,  however,  as  to  prevent  prompt  induration  in  air  or  water. 

Much  has  been  written  by  the  advocates  of  artifical  cements,  of 
the  importance  of  subjecting  cements  to  a  high  degree  of  heat  in  cal- 
cination in  order  to  bring  out  their  best  qualities. 

According  to  these  writers,  cements  that  cannot  sustain  a  high 
heat  without  injury  are  of  a  low  grade,  and,  singularly  enough,  these 
writers  are  unanimous  in  the  opinion  that  all  American  rock  cements 
are  calcined  at  a  low  heat,  and,  therefore,  as  a  matter  of  course,  are, 
by  them,  classed  as  low-grade  cements. 

It  may  be  stated,  in  passing,  that  this  is  an  error  on  the  part  of 
these  writers. 

There  are  many  American  rock  cements  that  stand  high  in  public 
favor  that  are  calcined  to  a  white  heat,  the  same  as  that  to  which 
Portlands  are  subjected. 

We  will  defer  the  discussion  of  this  particular  branch  of  the  sub- 
ject to  future  chapters,  and  confine  ourselves  to  the  elucidation  of  the 
various  phases  met  with  in  a  study  of  American  rock  cements. 

A  cement  rock  that  produces  the  double  silicates  is  a  mechanical 
combination  of  two  chemical  compounds,  viz.,  silicate  of  alumina 
(clay)  and  carbonate  of  lime,  while  that  which  produces  the  triple 
silicates  is  a  mechanical  combination  of  three  chemical  compounds, 
namely,  silicate  of  alumina,  carbonate  of  lime,  and  carbonate  of 
magnesia. 

The  last  two  compounds  named  are  combined  in  certain  fixed 
proportions,  while  the  clay  is  seldom  so  found,  as  the  silica  is 
usually  in  excess  of  true  combining  proportions  with  alumina. 

These,  with  other  compounds  relative  to  the  composition  of 
hydraulic  cements,  will  be  found  in  the  table  of  chemical  com- 
binations. 

It  does  not  follow  that  because  a  cement  may  contain  ingredients 
the  proportions  of  which  are  not  in  strict  conformity  to  the  law  govern- 
ing chemically  combining  proportions  as  ordinarily  interpreted,  it 
must  necessarily  contain  an  excess  of  one  or  more  of  the  bases,  for 
there  may  be,  and  often  are,  found  triple,  double,  and  single  silicates  in 
one  and  the  same  brand  of  cement ;  in  fact,  a  cement  is  improved  by 
diversifications  of  this  character. 


AMERICAN    CEMENTS.         •  33 

It  may  be  taken  as  a  truism  that  the  essential  constituents  of  a  * 
cement  rock  are  carbonate  of  lime  and  silicate  of  alumina. 

When  undergoing  calcination  the  lime  becomes  caustic  by  reason 
of  the  expulsion  of  the  carbon  dioxide,  in  which  condition,  and  while 
at  a  high  temperature,  it  attacks  and  disassociates  the  silicate  of  alumina, 
rendering  the  silica  free  as  a  silicic  acid,  the  latter  then  combining  in 
certain  fixed  ratios  with  the  bases  present,  forms  silicates. 

This  ratio  is  absolute.  Any  excess,  whether  of  the  acid  or  of  the 
bases,  must  and  does  remain  free  and  uncombined  in  the  resultant 
cement. 

Carbonate  of  magnesia  acts  in  a  similar  manner  to  carbonate  of 
lime,  and  when  the  two  are  present  with  a  proportionate  amount  of 
silica,  hydraulic  energy,  strength,  and  durability  follow.  And,  as  has 
been  pointed  out  before,  alumina,  which  is  always  present  by  reason  of 
its  combination  with  the  only  quality  of  silica  obtainable,  is  not 
particularly  objectionable  unless  it  is  in  excess.  It  is  not  so  good  a 
base  as  lime  or  magnesia,  and  when  in  excess  impairs  the  indurating 
value  of  the  cement. 

All  cement  rocks  contain,  in  varying  proportions,  oxide  of  iron, 
soda,  potash,  etc.,  which  are  not  objectionable  if  not  in  excess.  The 
former  gives  color  to  a  cement.  One  per  cent  will  produce  a  yellow- 
ish cast,  two  per  cent  a  drab,  and  four  per  cent  produces  a  dark  color. 
It  has  no  effect  whatever  on  the  quality  of  a  cement ;  it  is  simply 
an  adulterant,  and  is  usually  in  such  limited  amount  as  not  to  detract 
from,  while  it  certainly  does  not  add  to,  the  value  of  a  cement. 

With  the  aid  of  the  following  table  of  chemical  combinations, 
and  the  analyses  of  the  various  cements  of  this  and  other  countries, 
it  will  not  be  a  difficult  matter  to  deduce  conclusions  which,  it  is  hoped, 
may  not  be  devoid  of  interest. 

The  alkalies,  soda  and  potash,  when  present  to  the  extent  of 
three  to  five  per  cent,  add  much  to  the  quality  of  a  cement,  as  they 
have  much  to  do  as  an  aid  to  the  caustic  bases,  lime  and  magnesia, 
in  the  conversion  or  reaction  of  silicate  of  alumina  into  silicic  acid 
and  alumina,  or  forming  a  silicate  that  is  soluble  in  acids. 

But  the  constituents,  silicic  acid,  lime,  magnesia,  and  alumina, 
being  the  essential  ingredients  in  the  formation  of  hydraulic  cements, 
the  non-essentials  named  will,  for  the  sake  of  brevity  and  space,  be 
omitted  in  our  calculations. 


AMERICAN    CEMENTS. 


CHEMICAL  COMBINATIONS. 


I. 

Oxygen 

72.73  >=  CO2.       Carbonic   acid,  or  car- 

Carbon 

27.27  )                         bon  dioxide. 

2. 

Oxygen 

28.57  >       ^  Q      L.me 

Calcium 

71.43  $  ~~ 

3- 

Oxygen 
Magnesium 

40.04  ) 
,  v  =  Mgo.     Magnesia. 

4- 

Oxygen 
Silicon 

46.73  i=si°s-    suica- 

5- 

Oxygen 
Aluminum 

1=  A12  O3.        Alumina. 

6. 

Carbonic  Acid 

52.40  >  =  Mg  CO3.       Carbonate    of  mag- 

Magnesia 

47.60  I                             nesia. 

7- 

Carbonic  Acid 
Lime 

44.00  ) 
±        \  =  Ca  CO3.      Carbonate  of  lime. 
56.00  ^ 

8. 

Silica 
Alumina 

67  .8  "?  i          A  i    r^    J_ 

5  (  =  A1^.°3  +        Silicate  of  alumina. 
36.17$          3SiO2 

9- 

Silica 
Lime 

34.91  £         2CaO,SiO2-      Silicate  of  lime. 
65.09$ 

10. 

Silica 

42.91?=    2MgO  SiO2.     Silicate   of   mag- 

Magnesia 

57.09  S                                     nesia. 

ii. 

Silica 

2O.I4  x 

Lime 

54.34  >  =  ioo  Bisilicate  of  lime  and  alumina. 

Alumina 

16.52) 

12. 

Silica 

28.33^ 

Lime 

Q     f  =  ioo  Bisilicate  of  lime  and  mag- 
52  *o2  y 

Magnesia 

1  8  8c  )                  nesia. 

13- 

Silica 

24.41  >, 

Lime 

45.52  1  =100   Trisilicate   of  lime,    mag- 

Magnesia 

16.24  (                     nesia,  and  alumina. 

Alumina 

13.83  J 

14. 

Silica 

30.29  >  =  SiOa  K2  CO3.      Silicate  of  pot- 

Potash 

69.71  $                                       ash. 

IS- 

Silica 
Soda 

^6'g5  {  =  SiO2  Naa  CO3.    Silicate  of  soda. 

AMERICAN    CEMENTS. 


35 


CHAPTER   IV. 


TABLE  OF  ANALYSES.     HYDRAULIC  LIMES  AND  CEMENTS. 


No. 

Silica. 

Alumina. 

Iron 
oxide. 

Lime. 

Magnesia. 

Potash 
and   soda 

Sulphate 
of  lime. 

Carbonic- 
acid  water 
and  loss. 

I 

16  05 

I  02 

7.22 

77.20 

I.  52 

2 

24.  77 

7.77 

71.04 

•9 

2Q.  71 

5.75 

7.2Q 

CQ.  t?7 

O.QC 

1.  17 

4" 

2O.  C7 

1.  17 

j>yoj 

77.76 

O.  C.4. 

C 

28.14 

Q.  IO 

7.  2O 

1:7.74 

I.OO 

2.80 

2.42 

6 

7 

27.88 
2  "MI 

£ 
6.19 

7.O7 

4.64 
0.74 

•>2  j^ 
56-45 
56.17 

4.84 

1.7  c 

8 
9 

10 

ii 

12 

44-5° 
48.94 

J9-75 
24.90 
20.42 

15.00 
^48 

8.00 

12.  OO 

12.  OO 
11.92 
5.01 
3.22 
1.87 

8.80 
6.40 
60.71 

59.38 
67.17 

4.70 
2.42 
1.28 
0.38 

o.  c:8 

5-50 

3-93 
0.75 
0.50 

"I-64" 
1.46 

9-50 
7.64 
3.38 
2.16 
2.OO 

13 
14 

15 

16 

23-36 
22.74 

21.  II 

24.30 

8.07 

7-74 
11.30 

2.61 

4.83 
3-70 
3.36 

6.  20 

58.93 
S6.68 
58.03 
39-  4  5 

I.OO 

o.57 
2-93 
6.16 

0.50 
0.63 
0.71 

S.7O 

0.85 
1.66 
0.51 

2.46 
6.28 
2.05 
I  C..27, 

17 

34.66 

5.10 

I.OO 

30.24 

18.00 

6.16 

4.84. 

18 

^ 
27.l6 

6.  77 

1.  71 

76.08 

20.78 

c.27 

7.O7 

IQ 

^J.IU 
26.40 

6.28 

I.OO 

41;.  22 

Q.OO 

4.24 

7.86 

2O 

25.28 

7.85 

1.47 

44.  6  C 

9.  CQ 

4.2C 

7.O4 

21 

^o.  50 

6.84 

2.42 

•^4.^8 

18.00 

•3.08 

7.78- 

22 

27 

29.98 

•20.84 

6.88 
7.7  5 

2.50 
2.  II 

33-23 

74.49 

17.80 

17.77 

7.10 

4.00 



3-13 

7.O4 

24 
25 
26 

27 

27.30 
27.98 
28.38 

19.90 

7.14 
7.28 
11.71 

5.02 

.80 
.70 
.29 
.14 

35.98 

37-59 
43-97 
46.75 

18.00 
15.00 

2.21 

16.00 

6.80 

7.96 

9.00 

8.02 

2.98 
2.49 
2.44 
2.27 

28 

;- 
22.62 

7-44 

.40 

40.68 

22.00 

2.27 

3.63; 

29 

26.69 

7.21 

.30 

43.12 

ig.  CC 

1.  17 

I.OO 

^o 

24.74. 

8.56 

2.08 

61.62 

O.4O 

2.OO 

0.80 

71 

22.  QI 

8.00 

I.OO 

61.76 

2.  7O 

2.6^5 

72 

27.72 

6.00 

c.07 

^7.06 

7.76 

2.OO 

33 

74 

22.10 
24.04 

15.00 
Q.OO 

3.21 
1.16 

55.98 
67.64 

0.37 
1.26 

3-34 

35 

36 

f^t 
27.60 
77.42 

10.  60 
IO.O4 

0.80 
6.00 

33-04 
32.79 

7.z6 
9-  ">9 

7.42 

o.  e,o 

2.00 

7.66 

•27 

22.C8 

7.27 

7.75 

48.18 

I  C..OO 

7.66 

P 

22.44 

6.7O 

2.OO 

72.77 

*y*~> 

0.67 

J-w 

75.46 

36 


AMERICAN    CEMENTS. 


No. 

Silica. 

Alumina* 

Iron 
oxide. 

Lime. 

Magnesia. 

Potash 
and  soda. 

Sulphate 
of  lime. 

Carbonic- 
acid  water 
and  loss. 

39 
40 

28.43 
17.  CO 

6.7i 
5.50 

1.94 
7.OO 

36.31 

76.  ci 

23.89 

1.  80 

.92 

76  4Q 

41 

22.21 

16.48 

1.67 

^    •? 
79.64 

17.  CO 

2.  CO 

42 

32.06 

21.27 

2.  II 

7C.  c6 

7.OO 

2.OO 

AT. 

28.45 

2.24 

2.OO 

56.00 

IO.OO 

I.7I 

44 

18.59 

9.14 

I.OO 

40.70 

27.00 

7.  C7 

4C 

IQ.  C2 

I.Q7 

1.29 

41.  ci 

1.47 

74.24. 

46 

28.O2 

IO.2O 

8.80 

44.48 

I.OO 

O.  Co 

7.OO 

47 

IQ.3C 

7.OO 

4.  CO 

67.7  C 

t;.4O 

48 

21.14 

6.  70 

2.50 

66.04 

I.  II 

2.QI 

49 

22.69 

7.30 

2.87 

62.28 

1.  08 

3.78 

CO 

2O.8O 

7.  7Q 

2.61 

64.00 

c  2O 

ci 

27.  2O 

7.07 

2.41 

64.  IQ 

O.Q7 

2.  2O 

C2 

22.89 

8.00 

2.44 

63.38 

2.7O 

O.QQ 

C,3 

2C.I  C, 

8.00 

3.28 

49.  C7 

17.78 

O.26 

No. 


3- 

4- 
5- 

6. 

7- 
8. 

9- 

10. 

ii. 

12. 

13- 
14. 

IS- 

1 6. 


REFERENCE. 

Hydraulic  Lime,  Aberthaw,  England,  used  in  the  construc- 
tion of  the  Eddystone  Lighthouse. 

Hydraulic  Lime,  Lyme  Regis,  England,  used  in  the  con- 
struction of  the  London  docks. 

Eminently  Hydraulic  Lime,  Holywell,  Wales,  used  in  the 
construction  of  the  Liverpool  docks. 

Hydraulic  Lime,  Teil,  France. 

Hydraulic  Cement,  "  King's  Farm,"  on  Susquehanna  River, 
near  Williamsport,  Penn. 

Roman  Cement,  Rudersdorf,  Germany. 

Roman  Cement,  Isle  of  Sheppy,  England. 

Pozzuolana,  near  Rome,  Italy. 

Trass,  from  the  valley  of  the  Rhine. 

English  Portland  Cement,  "  K.,  B.  &  S."  brand. 


German  „ 

Natural  „ 

American  „ 

English  „ 

German  „ 
Buffalo  Hydraulic 
Utica 


Alsen  &  Son. 

Boulogne,  France. 

"  Giant,"  Egypt,  Penn. 

given  by  Reid  as  first  quality. 

»>      »j       »       »     »>         » 
Buffa    .  N.  Y. 
Utics   '11. 


OF  THE 


AMERICAN 


No.  18. 

»  19- 

„  20. 

„  21. 

„  22. 

„  23. 

„  24. 

»  25- 

„  26. 

»  27. 

„  28. 

»  29. 

„  30. 

»  Si- 

„  32. 

»  33- 

»  34- 

»  35- 

„  36. 

„  37- 

„  38. 

»  39- 

„  40. 

„  4i. 

„  42. 

»  43- 

»  44- 

„  45- 

„  46. 

»  47- 

„  48. 

»  49- 


52. 
53- 


Milwaukee 
Louisville 
Louisville 
Rosendale 


Cumberland,, 
Napanee  „ 
Akron 


37 


Milwaukee,  Wis. 

"  Fern  Leaf,"  Louisville,  Ky. 

"  Hulme,"  Louisville,  Ky. 

"  N.  L.  &  C.  Company,"  Rosen- 

dale,  N.  Y. 

"  Rock  Lock,"  Rosendale,  N.  Y. 
«  N.  Y.  &  R.,"  Rosendale,  N.  Y. 
"  Hoffman,"  Rosendale,  N.  Y. 
"Norton    High   Falls,"   Rosen- 

dale,  N.  Y. 
Cumberland,  Md. 
Napanee,  Ont. 
"  Newman,"  Akron,  N.  Y. 
"  Cummings,"  Akron,  N.  Y. 
South  Riverside,  Cal. 
"  Saylor's,"  Coplay,  Penn. 
"  Brockett,"  Kansas  City,  Mo. 


California    „  „ 

American  Portland  „ 

Fort  Scott  Hydraulic,, 

Gate  of  France  Hydraulic  Cement,  France. 

Vassy  Hydraulic  Cement,     France. 

Utica  „  „  La  Salle,  111. 

Shepherdstown  Hydraulic  Cement,  Shepherdstown,  Va. 

Howard  Hydraulic  Cement,  Cement,  Ga. 

Hydraulic  Cement  Rock  on  Platte  River,  Nebraska. 

Mankato  Hydraulic  Cement,  Mankato,  Minn. 

Hydraulic  Cement  Rock,  near  Salt  Lake  City,  Utah. 

St.  Louis  Hydraulic  Cement,  near  East  Carondelet,  111. 

Barnesville  Hydraulic  Cement,  Barnesville,  O. 

Warnock  „  „          Warnock,  O. 

Austin  „  „  Austin,  Minn. 

Hydraulic  Cement  Rock,  Blacksburg,  S.  C. 

Round  Top  Hydraulic  Cement,  Hancock,  Md. 

German  Portland  Cement, 


American 


James  River 


"  Dyckerhoff  "  brand. 
"  Germania  "  brand. 
"  Porta  "  brand. 
"  Empire,"  Warners,  N.  Y. 
"  Medusa,"  Sandusky,  O. 
"  Alpha,"  Phillipsburg,  N.  J. 
draulic  Cement,  Balcony  Falls,  Va. 


38  AMERICAN    CEMENTS. 

This  table  of  analyses  has  been  compiled  with  the  utmost  care, 
no  labor  having  been  spared  to  make  it  as  perfect  as  possible. 

Among  the  authorities  consulted  and  relied  upon  are  Beckwith, 
Bennett,  Bode,  Boynton,  Cox,  Davidson,  DeSmedt,  Dodge,  Dorr, 
Miller,  Newberry,  Ogden,  Reid,  and  Winchell,  analysts  and  chemists 
of  established  reputation. 

In  many  cases  a  selection  has  been  made  from  several  analyses  of 
the  same  brand  of  cement,  and  in  this,  as  in  all  other  respects,  great 
care  has  been  exercised  with  a  view  to  formulating  a  table  which  may 
be  confidently  relied  upon. 


AMERICAN    CEMENTS. 


CHAPTER   V. 

ANCIENT  GREEK  AND  ROMAN  MORTARS  —  CARBONATE  OF  LIME 
MORTARS  —  CONCRETE  OF  THE  MOUND-BUILDERS  —  SUL- 
PHATE OF  LIME  MORTARS,  ANCIENT  AND  MODERN. 

A  treatise  on  cements  would  hardly  be  complete  without  allusion 
to  those  cementing  agencies  which,  although  they  can  hardly  be 
classed  as  hydraulic,  as  that  term  is  now  understood,  were  used  in 
mortars  and  concretes  centuries  ago,  and  many  specimens  of  which 
are  still  in  a  good  state  of  preservation. 

We  refer  to  carbonate  of  lime  and  sulphate  of  lime,  each  of 
these  being  mixed  with  sand,  clay,  gravel,  and  finely  broken  stone. 
The  latter  having  been  used  above,  while  the  former  was  used  both 
above  and  below  ground.  It  is  quite  irreconcilable  with  our  modern 
ideas  as  to  the  causes  of  the  hardening  of  mortars,  yet  the  fact 
remains  that  carbonate  of  lime  has  been  made  into  a  mortar  by 
admixture  with  clay,  sharp  sand,  and  gravel,  and  after  three  thousand 
years  is  found  to  be  as  hard  as  a  rock. 

A  paper  by  Dr.  Wallace  read  before  the  Mechanics  Institution, 
Glasgow,  so  completely  covers  this  subject  as  to  render  a  literal  quo- 
tation desirable. 

On  Ancient  Mortars.     BY  WILLIAM  WALLACE,  Ph.  D.,  F.  R.  S.  E, 
F.  C.  S.     From  the  London  Chemical  News,  No.  281. 

"  Having,  by  the  kindness  of  William  Clarke,  Esq.,  C.  E.,  who 
has  recently  returned  from  the  East,  been  supplied  with  specimens 
of  mortars  and  plasters  from  well-known  ancient  buildings  in  Egypt, 
Greece,  Italy,  and  the  Island  of  Cyprus,  I  have  submitted  a  number 
of  them  to  analysis,  with  the  object  of  determining  several  points  of 
interest.  The  ages  of  the  mortars  vary  from  about  sixteen  hundred 
to  upwards  of  three  thousand  years,  thus  dating  back  to  the  most 
ancient  historical  periods.  I  propose  in  the  present  notice  to  give 
the  results  of  the  analysis  of  such  of  the  specimens  as  I  have  ex- 
amined. 


40  AMERICAN    CEMENTS. 

Mortar  of  the  Great  Pyramid.  —  Two  specimens  of  mortar  from 
the  Pyramid  of  Cheops  were  examined,  one  being  from  the  interior, 
and  the  other  from  the  outside  of  the  structure.  That  from  the  in- 
terior was  from  the  great  chamber  or  the  passage  leading  to  it.  Both 
specimens  present  the  same  appearance,  —  that  of  a  mixture  of  plaster 
of  a  slight  pinkish  color  with  crystalized  selenite  or  gypsum.  They 
do  not  appear  to  contain  any  sand,  the  silicic  acid  being  evidently  in 
combination  with  alumina  as  clay.  Part  of  the  selenite  was  probably 
burnt,  and  the  result  mixed  up  with  burnt  lime,  ground  chalk  or 
marl,  and  coarsely  ground  selenite.  The  latter  would  act  the  part  of 
sand  in  our  mortars,  />.,  prevent  undue  contraction  in  drying.  The 
quantity  of  water  is  almost  exactly  what  is  required  to  form  the 
ordinary  hydrate  of  sulphate  of  lime  with  two  equivalents  of  water. 
The  mortar  is  easily  reduced  to  fragments,  but  possesses  a  moderate 
degree  of  tenacity.  Prof.  C.  Piazzi  Smyth,  who  is  at.  present  making 
explorations  in  the  pyramid,  and  to  whom  I  have  communicated  the 
results  of  my  analysis,  has  informed  me  that  large  quantities  of  gyp- 
sum and  alabaster  are  found  in  its  vicinity ;  and  that  some  enormous 
slabs  of  alabaster  or  selenite  have  been  discovered  lining  the  walls 
of  a  large  tomb  recently  opened.  The  material  of  which  the  pyramid 
itself  is  constructed  being  limestone,  there  is  no  difficulty  in  account- 
ing for  the  presence  of  the  lime. 


EXTERIOR. 


Sulphate  of  lime,  hydrated 8I.5O1  82.89 : 

Carbonate  of  lime,  (CO2  calculated)  .     .     .     .       9.47  9.80 

Carbonate  of  magnesia  (       do.       )  .                        .59  .79 

Oxide  of  iron 25  .21 

Alumina •  .       2.41  3.00 

Silicic  acid 5.30  4.30 


99.52  100.99 

Ancient  Phoenician  Mortars  from  Cyprus.  —  Two  specimens 
were  obtained  from  Cyprus.  The  first  is  from  the  ruins  of  a  temple 
near  Larnaca,  the  highest  stone  of  which  at  present  remaining  is  five 
feet  below  the  level  of  the  ground,  and  the  lowest  about  eighteen  feet. 
Mr.  Clarke  supposes  this  to  be  the  most  ancient  mortar  in  existence, 

1  Water  by  actual  estimation,  16.66,  17.38. 


AMERICAN    CEMENTS.  41 

and  it  certainly  is  one  of  the  best  I  have  ever  seen.  It  is  exceedingly 
hard  and  firm,  and  appears  to  have  been  made  of  a  mixture  of  burnt 
lime,  sharp  sand,  and  gravel,  some  of  the  fragments  being  about  half 
an  inch  diameter.  On  solution  in  hydrochloric  acid,  it  gave  a  small 
quantity  of  soluble  silica,  amounting  to  .52  per  cent. 

The  other  specimen  from  Cyprus  is  a  cement  used  for  joining 
water  pipes.  These  pipes  were  found  near  Larnaca,  ten  feet  below 
the  surface  of  the  ground,  and  bear  evidence  of  extreme  antiquity; 
they  are  of  red  clay,  about  eleven  inches  in  diameter,  and  are  con- 
nected by  spigot  and  faucet  joints,  the  intervening  spaces  being  filled 
with  the  cement,  and  afterwards  coated  with  a  black  substance  which 
was  found  to  be  bitumen.  This  mortar  or  cement  is  very  hard  and 
perfectly  white  in  color.  It  will  be  observed  that  in  both  of  these 
Phoenician  mortars  the  lime  is  almost  completely  carbonated. 


Lime ,.     .     .     .     .     26.40  51.58 

Magnesia 97  .70 

Sulphuric  acid .21  .82 

Carbonic  acid 20.23  40.60 

Sesquioxide  of  iron .99 

Alumina 21.6  .40 

Silicic  acid  and  fine  sand 16.20  .96 

Coarse  sand 3.37 

Small  stones 28.63 

Organic  matter 56  .24 

Water 54  3.09 


100.26  98.39 

Ancient  Greek  Mortars.  —  The  first  specimen  is  taken  from  a 
part  of  the  Pnyx,  the  platform  from  which  Demosthenes  and  Pericles 
delivered  many  of  their  orations.  It  has  been  long  exposed  to  the 
action  of  the  weather,  is  very  hard,  and  of  a  grayish-white  color. 
The  other  specimen  is  plaster  from  the  interior  of  an  ancient  temple 
at  Pentelicus,  near  Athens.  It  has  not  been  exposed  to  the  weather, 
the  temple  being  in  a  cave ;  it  is  of  a  pale  cream  color,  and  moder- 
ately hard.  The  analytical  results  are  the  following : 


42  AMERICAN   CEMENTS. 

PNYX.  TEMPLE   AT   PENTELICUS. 

Lime .     .     45-7°  49-65 

Magnesia i.oo  1.09 

Sulphuric  acid 1.04 

Carbonic  acid 3?.oo  38.33 

Sesquioxide  of  iron 92  .82 

Alumina 2.64  .98 

Silicic  acid  and  sand 12.06  3.90 

Water 36  3.07 


99.68 

In  the  mortar  from  the  Pnyx  the  carbonic  acid  is  exactly  the 
amount  required  by  the  lime  and  the  magnesia,  supposing  both  to  be 
completely  carbonated ;  in  that  from  the  temple  the  carbonating  is 
nearly  but  not  quite  complete. 

Ancient  Roman  Mortars.  —  These  differ  from  those  already 
mentioned  in  being  evidently  prepared  by  mixing  with  burnt  lime,  not 
sand,  but  puzzuolana,  or  what  is  commonly,  although  improperly, 
called  volcanic  ash.  Of  these,  four  specimens  were  examined,  but 
two  only  of  the  analyses  were  completed,  owing  to  deficiency  of  mate- 
rial. The  first  in  the  following  table  was  taken  from  Adrian's  Villa 
at  Tivoli,  near  Rome ;  it  is  a  tolerably  hard  and  firm  mortar,  of  a 
rather  dark-gray  color. 

The  second  is  plaster  from  the  interior  of  a  wall  at  Herculaneum; 
it  is  hard,  evidently  exposed  on  one  side  to  the  action  of  hot  volcanic 
mud,  and  of  a  red  tint.  The  third  specimen  is  from  the  roof  of  the 
Latin  tombs  near  Rome,  of  a  pale  reddish-brown  color.  The  fourth 
is  a  cement  or  mortar  from  a  mosaic  forming  the  floor  of  the  baths  of 
Caracalla,  Rome.  All  these  mortars  were  hard  and  firm,  and  con- 
tained an  appreciable  amount  of  silicic  acid  in  combination :  — 

ADRIAN'S  VILLA.    HERCULANBUM.    LATIN  TOMBS.    MOSAIC. 

Lime     .     .     .    ,  •** '    *"  15-3°  29.88  19.71         25-I9 

Magnesia       .     ,     .     .  .30  .25  .71              .90 

Potash       .     .     *    *    .  i .01  3.40  not  estimated. 

Soda •  -.-  2.12  3.49  not  estimated. 

Carbonic  acid     .     .     .  11.80  23.80  13.61          17.97 

Peroxide  of  iron     .     .  4.92  2.32  1.23           3.67 


AMERICAN    CEMENTS.  43 

ADRIANS   VILLA.      HERCULANHUM.  LATIN   TOMBS.  MOSAIC. 

Alumina    .....         H-70                   2.86              16.39  IO-64 

Silicic  acid  and  sand  .         41.10                 33-36             36.26  3°-24 

Organic  matter  .     .     .            2.28                    1.50  2.48 

Water 5.20                   i.oo               8.20  5.50 


98.73  101.86 

General  Remarks.  —  These  analyses  appear  to  show  that  the 
lime  in  mortars  and  plasters  becomes,  in  the  course  of  time,  com- 
pletely carbonated,  and  does  not  form  a  combination  consisting  of 
CaO,HO  -f  CaO,  Co2,  a  conclusion  that  has  been  arrived  at  by  some 
authorities.  They  also  show  that  in  all  cases  where  the  mortar  is 
freely  exposed  to  the  weather  a  certain  proportion  of  alkaline  or 
earthy  silicate  is  formed,  which  in  all  probability  confers  additional 
hardness,  and  that  those  mortars  are  the  hardest  which  have  been 
long  below  ground.  It  is  well  known  to  builders  that  those  walls  are 
strongest  that  are  built  during  a  rainy  season,  and  that  when  mortar 
dries  quickly  it  becomes  crumbly  and  possesses  little  binding  power. 
When  kept  wet  for  some  time,  a  small  proportion  of  silicate  of  lime 
will  be  formed,  which  will  not  only  make  the  mortar  itself  harder,  but 
will  unite  it  more  firmly  with  the  stone.  It  is  curious  that  the  mortar 
which  is  probably  the  most  ancient  (the  specimen  from  a  Phoenician 
temple)  is  by  far  the  hardest  and  firmest;  in  fact,  like  a  piece  of 
rock.  It  is  a  concrete,  rather  than  a  mortar,  and  its  excellence  seems 
to  indicate  that  a  large-grained  sand  is  best  for  building  purposes, 
and  that  even  small  gravel  may,  in  certain  cases,  be  used  with 
advantage." 

Prof.  E.  T.  Cox,  in  his  report  of  the  geological  survey  of  Indiana, 
renders  an  interesting,  and,  in  view  of  the  question  of  antiquity,  a 
valuable  acquisition  to  our  knowledge  of  ancient  mortars  and  con- 
cretes ;  and  the  question  arises,  was  the  old  or  the  new  world  the  first 
to  produce  from  materials  which  to-day  would  be  considered  as  use- 
less for  such  a  purpose,  a  mortar  or  concrete,  which,  being  placed 
below  ground,  would  become  hard  and  stone-like  in  character  and 
remain  so  throughout  all  the  centuries  that  have  elapsed  since  their 
first  fabrication. 

Prof.  Cox  says,  "  It  is  not  alone  in  Europe  that  we  find  a  well- 


44  AMERICAN    CEMENTS. 

founded  claim  of  high  antiquity  for  the  art  of  making  hard  and  dur- 
able stone  by  a  mixture  of  clay,  lime,  sand,  and  fragments  of  stone ; 
for  I  am  satisfied  that  this  art  was  possessed  by  a  race  of  people 
who  inhabited  this  continent  at  a  period  so  remote  that  neither  tradi- 
tion nor  history  can  furnish  any  account  of  them. 

"  They  belonged  to  the  Neolithic  or  polished  stone  age.  They 
lived  in  towns  and  built  mounds  for  sepulture  and  worship,  and  pro- 
tected their  homes  by  surrounding  them  with  walls  of  earth  and 
stone.  In  some  of  these  mounds  specimens  of  various  kinds  of 
pottery,  in  a  perfect  state  of  preservation,  have  from  time  to  time 
been  found,  and  fragments  are  so  common  that  every  student  of 
archaeology  can  have  a  bountiful  supply. 

"  Some  of  these  fragments  indicate  vessels  of  very  great  size. 
At  the  Saline  Springs  of  Gallatin  County,  111.,  I  picked  up  frag- 
ments that  indicated,  by  their  curvature,  vessels  five  to  six  feet  in 
diameter,  and  it  is  probable  that  they  are  fragments  of  artificial 
stone  pans  used  to  hold  brine  that  was  manufactured  into  salt  by 
solar  evaporation. 

"  Now,  all  the  pottery  belonging  to  the  Mound-Builders'  age 
which  I  have  seen  is  composed  of  alluvial  clay  and  sand  or  a  mix- 
ture of  the  former  with  pulverized  fresh  water  shells. 

"  A  paste  of  such  a  mixture  possesses  in  a  high  degree  the 
properties  of  hydraulic  pozzuolana  and  Portland  cement,  so  that 
vessels  formed  of  it  hardened  without  being  burnt,  as  is  customary 
with  modern  pottery.  The  fragments  of  shells  served  the  purpose  of 
gravel  or  fragments  of  stone  as  at  present  used  in  connection  with 
hydraulic  lime  in  the  manufacture  of  artificial  stone. 

"  It  will  be  seen  by  the  following  analysis  of  a  piece  of  ancient 
pottery  from  the  '  Bone  Bank,'  in  Posey  County,  Indiana,  that,  so  far 
as  chemical  constituents  are  concerned,  it  agrees  very  well  with  the 
composition  of  hydraulic  stones. 

"  ANCIENT   POTTERY,    '  BONE   BANK,'    POSEY    COUNTY,    IND. 

Moisture  at  212°  F i.oo 

Silica   . 36.00 

Carbonate  of  lime 25-5° 

Carbonate  of  magnesia 3-2° 

Alumina 5-°° 


AMERICAN    CEMENTS.  45 

Peroxide  of  iron 5-5° 

Sulphuric  acid 0.20 

Organic  matter,  alkalies,  and  loss 23.60 

Total 100.00 

"  It  is  my  opinion,  based  upon  the  result  of  its  analysis,  that  it 
is  simply  an  artificial  stone  made  from  a  mixture  of  river  mud  and 
pulverized  fresh  water  shells.  Instead  of  softening  in  water,  as  they 
would  if  made  of  clay  alone,  the  shells  give  to  the  composition 
hydraulic  properties,  and  vessels  made  of  it  harden  on  exposure  to 
air  and  moisture.  When  filled  with  water  and  meat,  pots  made  of 
this  material  could  be  placed  over  the  fire  and  heated  without  fear 
of  breaking  them. 

"  Those  ancient  artisans  must  have  been  aware  of  the  advantage 
derived  from  a  thin  body  to  resist  breakage  from  expansion  and  con- 
traction from  the  heat  of  the  fire. 

"  I  have  a  beautiful  vessel  from  the  « Bone  Bank,'  made  of 
artificial  stone,  which  has  ears,  and  is  otherwise  formed  like  an  old- 
fashioned  cast-iron  dinner  pot.  It  is  five  inches  across  the  mouth, 
and  seven  inches  in  diameter  at  the  bulge,  five  inches  deep,  and  only 
one  eighth  of  an  inch  thick.  The  bottom  is  smoked  black,  which 
goes  to  show  that  it  was  suspended  over  the  fire  for  cooking  purposes." 

It  will  be  noted  that  Prof.  Cox  describes  the  lime  and  magnesia 
as  carbonates,  and  states  that  they  are  in  the  form  of  pulverized 
shells,  and  so  used  in  the  mixture,  while  Dr.  Wallace  takes  the 
position  that  the  lime  was  calcined  and  subsequently  became  car- 
bonated. 

By  giving  the  carbonic  acid  its  full  equivalents  of  lime  and 
magnesia  to  form  carbonates  of  those  bases,  and  the  sulphuric  acid 
its  full  equivalent  of  lime  to  form  sulphate  of  lime,  in  the  mortar 
from  the  temple  at  Pentelicus,  as  given  by  Dr.  Wallace,  it  will  be 
found  that  the  excess  of  lime  is  so  slight  as  to  preclude  the  belief 
that  the  lime  was  calcined  prior  to  its  use,  and  that  the  position  taken 
by  Prof.  Cox  is  the  correct  one,  and  it  is  not  difficult  to  believe  that 
in  all  these  ancient  mortars  named,  pulverized  carbonate  of  lime  was 
the  cementing  agent  used. 

The  "  Old  Stone  Mill  "  at  Newport,  Rhode  Island,  which,  accord- 
ing to  many  learned  antiquaries,  was  built  by  the  Norsemen  five 


46  AMERICAN    CEMENTS. 

hundred  years  before  the  landing  of  Columbus,  was  constructed  with  a 
mortar  composed  of  pulverized  shells,  clay,  sharp  sand,  and  fine  gravel. 

The  antiquity  of  this  ancient  structure  has  been  a  subject  of 
much  discussion. 

J.  P.  Mac  Lean,  in  American  Antiquarian,  stoutly  maintains 
that  it  was  built  by  or  upon  the  lands  of  Gov.  Benedict  Arnold 
during  the  period  of  his  residence  at  Newport,  which  was  from  1653 
until  his  death  in  1678. 

Mr.  MacLean  states  that  in  the  year  1848  some  mortar  taken 
from  an  old  stone  house  in  Spring  Street,  built  by  Henry  Bull  in 
1639  (the  year  in  which  Newport  was  founded),  some  from  the 
tomb  of  Governor  Arnold,  and  some  from  various  other  buildings 
was  compared  with  the  mortar  of  the  Old  Mill,  and  found  to  be  iden- 
tical in  quality  and  character. 

Whether  the  Old  Mill  has  been  built  more  than  nine  hundred 
or  only  a  little  over  two  hundred  years,  the  fact  remains  that  the 
mortar  with  which  it  was  constructed  is  composed  of  the  materials 
as  stated,  and  a  careful  examination  of  this  structure,  by  the  writer, 
during  the  summer  of  1894,  revealed  some  curious  features  which 
are  not  easily  adjusted  to  modern  ideas  of  stability. 

The  stones  are  mostly  small  and  unshapen,  and  in  many  places 
the  mortar  joints  are  over  an  inch  in  thickness.  Taken  altogether, 
the  work  was  carelessly  done,  and  how  such  a  wall  could  have  been 
held  in  place  for  even  two  hundred  years  with  such  a  mortar,  and  in 
such  a  climate,  seems  almost  incredible.  There  are  no  indications 
of  crumbling  on  the  part  of  this  curious  mortar ;  on  the  contrary,  it 
is  hard  and  firm,  and  from  present  appearances  is  liable  to  remain  so 
for  centuries  to  come.  The  fact  will  not  be  overlooked  that  this 
mortar  is  composed  of  identically  the  same  materials  as  are  those 
mentioned  by  Prof.  Cox  as  having  been  used  by  the  Mound-Builders, 
which  fact  is  rather  damaging  to  the  theory  adduced  by  Mr.  Mac- 
Lean  in  his  attempt  to  overthrow  the  arguments  advanced  favoring 
the  antiquity  of  the  "  Old  Stone  Mill." 

It  would  be  a  rash  man  who,  to-day,  would  build  a  structure  of 
any  importance  with  a  mortar  composed  of  pulverized  shell-marl, 
clay,  and  sand  ;  and  yet,  with  the  evidence  before  us  of  its  having 
been  so  used  in  the  "  Old  Stone  Mill "  in  New  England,  where  it  has 
been  subjected  to  alternate  freezing  and  thawing  through  all  these 


AMERICAN    CEMENTS.  47 

years,  and  even  accepting  Mr.  Mac  Lean's  theory  as  to  the  time 
which  has  elapsed  since  its  construction,  it  antedates  by  a  full  hun- 
dred years  the  time  when  Smeaton  "  lightened  up  the  darkness  sur- 
rounding the  subject  of  mortars  and  their  behavior  under  varied 
circumstances,"  and  thus,  it  would  seem  that  the  permanence  and  dura- 
bility of  shell-lime,  i.e.,  carbonate  of  lime,  mortar  must  be  conceded. 

But  it  is  not  at  all  clear  how  a  mortar  composed  of  such  mate- 
rials can,  without  calcination,  become  hard.  It  is  quite  true,  as 
stated  by  Prof.  Cox  in  his  reference  to  the  analysis  of  ancient 
pottery,  that  "  so  far  as  chemical  constituents  are  concerned,  it 
agrees  very  well  with  the  composition  of  hydraulic  stones ;  "  yet  this 
does  not  by  any  means  constitute  an  hydraulic  cement,  which,  it  may 
be  inferred,  was  meant  by  him  where  he  states  that  "  a  paste  made 
from  such  a  mixture  possesses  in  a  high  degree  the  properties  of 
hydraulic  pozzuolana  and  Portland  cement,  so  that  vessels  formed 
of  it  hardened  without  being  burnt,  as  is  customary  with  modern 
pottery." 

It  is  true  that  Portland  cement  is  made  by  an  admixture  of  clay 
and  carbonate  of  lime ;  yet,  however  thoroughly  and  intimately  these 
two  ingredients  may  be  commingled,  it  is  clear  to  every  one  who  is 
at  all  familiar  with  the  subject  that  this  mixture,  without  further 
treatment  beyond  its  mere  mechanical  incorporation,  cannot  be  in- 
duced to  harden  beyond  a  natural  moderate  hardness  due  to  the 
drying  out  of  the  clay. 

By  submersion  it  soon  becomes  plastic  again.  At  such  a  stage, 
and  in  such  a  condition,  there  is  no  chemical  affinity  between  these 
substances. 

There  are  present  two  acids  and  two  bases.  Each  of  the  former 
is  chemically  combined  with  one  of  the  latter,  in  certain  fixed  pro- 
portions. 

The  lime  is  combined  with  78.57  per  cent,  of  its  own  weight  of 
carbonic  acid,  which  in  hundred  parts  is  lime  56,  carbonic  acid  44  = 
100  carbonate  of  lime. 

But  clay  is  rarely  found  in  true  combining  proportions,  the  silicic 
acid  almost  universally  predominating.  The  latter  combines  with 
nearly  57  per  cent,  of  its  own  weight  of  alumina. 

The  ratio  in  one  hundred  parts  being  silicic  acid  63.83  and 
alumina  36.17  =  100  silicate  of  alumina. 


48  AMERICAN    CEMENTS. 

In  the  analysis  given  by  Prof.  Cox,  the  silica  is  36.00  and  the 
alumina  is  5.00.  Therefore,  as  the  5.00  of  alumina  will  combine 
with  only  8.82  of  the  silica,  forming  clay  13.82,  there  must  necessarily 
remain  27.18  of  free  and  uncombined  silicic  acid,  and  this  cannot 
combine  with  the  lime,  which  already  has  its  full  equivalent  of  acid; 
and  although  the  latter  is  volatile,  it  will  not  part  from  its  combina- 
tion with  the  lime,  except  through  the  agency  of  heat,  even  though 
the  carbonate  of  lime  is  in  intimate  contact  with  free  silicic  acid 
through  countless  centuries,  as  is  shown  in  the  natural  cement  rocks 
throughout  the  world,  nearly,  if  not  all  of  which  contain  more  silica 
than  will  combine  with  the  alumina  present,  a  fact  which  in  no 
manner  affects  the  relative  proportions  of  the  constituent  parts  of  the 
carbonate  of  lime. 

A  suggestion  that  the  ancients  had  succeeded  in  imitating 
Nature  in  her  mode  of  hardening  hydraulic  cement  stones  is  met 
with  the  familiar  fact  that  such  stones,  if  exposed  to  the  weather  in 
a  climate  where  they  are  subjected  to  freezing  and  thawing,  will 
crumble  into  gravel  and  mud  —  a  result  which  does  not  seem  to  follow 
in  similar  mixtures  compounded  by  the  ancient  Romans  or  by  the 
Mound-Builders. 

Prof.  H.  C.  Bowen,  of  the  School  of  Mines,  Columbia  Col- 
lege, New  York  City,  in  a  correspondence  with  the  author,  advances 
an  exceedingly  plausible  theory  in  regard  to  the  hardening  of  the 
pottery  belonging  to  the  Mound-Builders'  age. 

He  states  that  this  pottery  "  is  hard  and  unyielding,  doubtless 
because  of  a  slow  cementing  process  brought  about  by  infiltration 
and  subsequent  evaporation  of  water  laden  with  calcium  carbonate  in 
solution. 

"  The  same  thing  could  be  accomplished  in  a  smaller  way  by 
taking  a  somewhat  porous  ball  of  dry  clay,  broken  shells,  limestone 
dust,  or  quartz  grit  and  from  time  to  time  pouring  upon  it  some  water 
that  is  charged  with  calcium  carbonate  in  solution ;  then  to  allow 
the  ball  to  dry  out,  and  to  repeat  this  several  weeks  ;  at  the  end  the 
ball,  which  at  first  was  loose  and  without  strength,  will  be  found 
strong  and  very  resisting. 

"  The  calcium  carbonate  water  spoken  of  above  can  be  pro- 
duced by  putting  amorphous  limestone  powder  (impalpable)  into  a 
gallon  bottle  having  about  three  quarts  of  rain  water,  and  then  charge 


AMERICAN    CEMENTS.  49 

the  water  and  the  space  above  it  with  clean  carbon  dioxide  gas,  and 
from  time  to  time  shaking  the  bottle  vigorously,  and  also  from  time 
to  time  recharging  the  water  with  carbon  dioxide. 

"  The  explanation  is  somewhat  simple,  it  being  that  the  water 
carries  calcium  carbonate  in  solution  and  thus  distributes  it  upon 
every  portion  of  all  the  interior  of  the  ball  spoken  of  above.  The 
water  evaporating  over  the  surface  and  crevices  within  the  ball 
causes  a  slight  incrustation,  and  in  time  pretty  thoroughly  fills  up  all 
the  interior  spaces,  thus  turning  the  mass  into  a  solid  structure. 
The  manufacture  of  prehistoric  pottery  vessels  involved  probably  a 
feeble  baking  process,  baking  being  somewhat  important." 

Instances  are  often  met  with  in  nature  where  hardening  is  caused 
by  infiltration  of  water  charged  with  calcium  carbonate,  in  various 
kinds  of  petrifactions,  as  in  the  turning  of  wood  to  stone.  Sand 
sometimes  becomes  solidified  by  the  action  of  carbonated  sea  waters, 
and  it  is  extremely  probable  that  by  observing  these  facts  in  nature 
the  Mound-Builders  grasped  the  idea  and  applied  it  to  the  harden- 
ing of  their  kitchen  utensils,  which  could  have  been  done  by  the 
process  described  by  Professor  Bowen. 

But  it  will  be  observed  that,  however  true  this  theory  may  be  as 
applied  to  the  induration  of  the  pottery  produced  by  the  Mound- 
Builders,  it  affords  no  explanation  whatever  for  the  hardness  of  the 
ancient  masonry  and  concrete  described  by  Dr.  Wallace  and  the 
durability  of  the  mortar  in  the  "  Old  Stone  Mill  "  at  Newport. 

SULPHATE    OF   LIME   MORTARS. 

The  mortar  of  the  great  Pyramid  of  Cheops,  as  shown  by  Dr. 
Wallace,  Mr.  Cresy,  and  others,  is  composed  of  hydrated  sulphate  of 
lime  (gypsum),  carbonate  of  lime,  and  clay. 

According  to  Strabo,  the  walls  of  Tyre  were  built  of  stone  set  in 
gypsum,  a  very  common  material,  apparently,  in  Asia  Minor  and  the 
center  of  the  old  Assyrian  civilization. 

The  composition  of  pure  gypsum  is  as  follows  : 

Sulphuric  acid 46.52 

Lime      . 32.55 

Water 20.93 


Total .   100.00 


50  AMERICAN    CEMENTS. 

When  heated  to  230  degs.  Fahr.  gypsum  will  part  with  its  water 
of  crystallization.  It  then  becomes  sulphate  of  lime,  its  composition 
consisting  of  sulphuric  acid  58.84,  lime  41.16=100.  If  then 
pulverized  and  mixed  with  water  into  a  paste,  it  will  quickly  harden 
to  a  solid  mass,  becoming  crystallized  again  by  recombining  with  its 
equivalent  of  water. 

But  should  the  heat  be  carried  above  320  degs.  Fahr.  it  will  no 
longer  harden  by  admixture  with  water.  It  will  not  crystallize.  The 
naturally  occurring  anhydrite  behaves  in  the  same  manner  when 
reduced  to  powder.  Although  in  rock  form  it  has  a  crystallization, 
it  is  very  different  from  that  of  gypsum. 

One  part  of  sulphate  of  lime  will  dissolve  in  400  parts  of  water. 

One  part  of  slaked  lime  will  dissolve  in  760  parts  of  water. 

Silicate  of  lime,  the  basis  of  hydraulic  cement,  will  not  dissolve 
in  water. 

Sulphate  of  lime  was  extensively  used  by  the  ancient  inhabitants 
of  Mexico,  as  well  as  those  of  Egypt,  in  their  masonry;  also  for 
exterior  as  well  as  interior  plastering,  and  history  seems  likely  to  re- 
peat itself,  in  some  respects,  at  least,  in  the  use  of  this  material. 

In  several  places  in  the  Western  States,  and  notably  in  Kansas 
and  Texas,  beds  of  impure  gypsum  are  found  of  a  soft,  mudlike 
consistency.  The  impurities  consist  chiefly  of  clay.  Within  the 
past  few  years  some  of  these  deposits  have  been  developed,  resulting 
in  the  building  up  of  a  new  industry  that  bids  fair  to  become  quite 
extensive. 

The  material  is  taken  from  the  beds  and  heated  sufficiently  to 
expel  the  water  of  crystallization  contained  in  the  gypsum,  the  same 
operation,  of  course,  expelling  the  moisture  from  the  clay,  upon  which 
the  substance  falls  into  an  impalpable  powder.  It  is  then  ready  for 
the  market,  and  is  sold  for  purposes  of  plastering.  It  has  many 
advantages  over  common  quicklime  for  such  a  purpose,  as  it  sets 
quickly,  becoming  dry  and  hard  in  a  short  time.  It  carries  sand 
largely,  quite  equaling  quicklime  in  that  respect,  and,  unlike  the 
latter,  it  requires  no  hair  in  plastering. 

These  gypseous-clay  beds  were  probably  a  mixture  of  clay  and 
carbonate  of  lime,  and  in  the  condition  of  natural  hydraulic  cement 
rock.  Subsequently,  these  rocks  were  subjected  to  the  action  of 
sulphuric  acid,  which  expelled  the  carbonic  acid,  and  itself  com- 


AMERICAN    CEMENTS.  51 

bined  with  the  lime,  forming  gypsum.  The  presence  of  the  clay,  in 
intimate  contact  with  the  gypsum,  prevented  the  latter  from  harden- 
ing, as  would  have  been  the  case  had  the  gypsum  been  pure.  The 
sulphuric  acid  was  undoubtedly  produced  by  the  oxidation  of  iron 
pyrites  or  by  the  oxidation  of  sulphuretted  hydrogen  from  sulphur 
springs  in  the  neighborhood  of  the  deposits. 

The  manufacturers  of  this  gypseous-clay  cement  claim  that  it 
sets  much  harder  than  ordinary  plaster  of  Paris  (calcined  gypsum), 
and  attribute  to  it  many  features  of  excellence  which  cannot  be 
attained  by  any  admixture  of  pure  plaster  of  Paris  and  sand. 

It  is  possible  that  the  heated  clay  may  act  somewhat  in  the 
nature  of  a  pozzuolana,  and  by  reason  of  its  finely  comminuted  con- 
dition, and  its  intimate  contact  with  the  sulphate  of  lime,  effects  may 
be  produced  that  are  not  possible  with  a  mixture  of  sulphate  of  lime 
and  sand. 

The  Agatite  Cement  Plaster  Company,  of  Kansas  City,  Mis- 
souri, controls  a  bed  of  this  material  at  or  near  Dillon,  Kansas,  which 
is  estimated  to  contain  about  six  million  tons. 

Prof.  Edwin  Walters,  in  a  report  on  this  material,  says  :  — 

"  Agatite  is  of  a  light  ash-gray  color.  Its  natural  consistency  is 
about  that  of  hard  plastic  clay.  When  calcined  it  assumes  a  pulver- 
ized form.  When  mixed  with  water  it  sets  as  does  hydraulic  lime 
or  cement.  There  seems  to  be  ample  time  between  the  mixing  and 
the  setting  for  the  mortar  to  be  applied  to  its  intended  use. 

"  A  sample  of  several  weeks'  setting  broke  under  a  tensile  strain 
of  370  Ibs.  to  the  square  inch.  It  may  be  safely  said  that  in  both 
tensile  and  compressive  strength  agatite  is  fully  one  half  that  of  the 
very  best  Portland  cement  under  the  Neat  test  and  equal  under  the 
part  sand  test.  It  is  superior  in  strength  to  most  of  the  hydraulic 
limes  and  ordinary  cements.  But,  inasmuch  as  agatite  is  intended 
for  interior  work,  it  is  not  necessary  that  it  should  be  of  such  great 
strength.  It  is  very  much  stronger  than  lime  and  sand  plaster,  which 
is  its  principal  competitor. 

"  Agatite  does  not  differ  widely  in  composition  from  the  cement 
taken  from  the  famous  Cheops  Pyramid  of  Egypt.  The  Egyptian 
cement  runs  higher  in  sulphate  of  lime  and  lower  in  oxide  of  iron. 

"It  is  very  probable  that  a  cement  that  would  stand  in  the 
climate  of  Egypt  would  also  prove  durable  in  the  United  States. 


UNIVERSITY 


52  AMERICAN    CEMENTS. 

"  I  only  make  the  comparison  to  show  that  if  the  agatite  is  kept 
reasonably  protected  from  frosts  and  excessive  moisture  that  it 
would  last  for  ages.  It  has  splendid  adhesive  qualities.  It  will  stick  to 
wood,  stone,  or  brick  without  the  aid  of  hair  or  any  other  substance. 

"  It  is  not  decomposed  by  any  of  the  basic  acids,  however  strong 
they  may  be.  Alkalies  do  not  affect  it. 

"  Besides  being  a  choice  material  for  plastering  walls  and  ceil- 
ings, it  is  admirably  adapted  to  all  kinds  of  interior  finish.  When  in 
the  plastic  state  it  may  be  embossed,  stippled,  drawn,  or  molded. 
Any  design  in  bas-relief  may  be  executed  if  prompt  action  is  taken 
after  mixing.  The  time  allowed  for  execution  is  much  greater  than 
that  for  stucco,  unless  the  stucco  is  mixed  with  glue  or  some  retarder 
that  is  likely  to  cause  decomposition. 

"Another  superiority  over  stucco  is  its  hardness.  Not  only  does 
it  allow  much  more  time  for  execution,  but  it  is  very  much  harder 
after  it  sets. 

"  Paper  may  be  applied  to  either  one  or  two  coat  work  for  a 
finish.  It  is  probable  that  one  coat  will  be  the  best  method.  Paints 
may  be  added  to  agatite  mortar  to  give  any  desired  color,  when 
paper  is  not  desired.  If  a  white  finish  is  wished,  a  putty  or  stucco 
coat  may  be  applied  on  the  surface  of  the  agatite. 

"  This  material  is  adapted  for  wainscoting,  interior  arches,  and 
segments  for  the  back-filling  and  setting  of  tiles,  for  statuettes,  etc., 
etc." 

There  would  seem  to  be  no  doubt  that  gypsum  plaster  will  find 
an  extended  use  in  the  near  future,  and  in  a  measure  supplant  the 
use  of  quicklime  as  a  plastering  material  in  interior  work  of  much 
importance  and  magnitude. 

It  is  doubtful,  however,  if  it  can  ever  be  used  for  exterior  work 
in  Northern  latitudes  until  some  means  are  discovered  for  rendering 
it  proof  against  the  action  of  alternate  freezing  and  thawing. 

The  climates  of  Egypt  and  Mexico  are  such  as  to  permit  the  use 
of  this  material  for  exterior  work,  and  there  is  no  doubt  but  that  it 
could  be  so  used  with  safety  in  our  Southern  States  on  brick,  stone, 
or  wooden  structures,  and  very  pleasing  architectural  effects  thereby 
produced  at  a  comparatively  slight  cost.  Sulphate  of  lime  as  a 
cementing  agent  has  not  as  yet  received  the  consideration  due  to  its 
merits  in  this  country.  Heretofore  it  has  been  extensively  used  in 


AMERICAN    CEMENTS.  53 

interior  decoration  and  for  similar  purposes,  but  there  seems  to  have 
been  no  advance  made  in  the  direction  of  permanent  exterior  work. 
It  was  used  as  an  outside  covering  of  the  walls  of  the  World's 
Fair  Buildings  at  Chicago,  which,  however,  were  temporary  structures. 

By  adding  2647  per  cent,  of  its  own  weight  of  water  to  this  ma- 
terial, it  becomes  so  hard  and  firm  that,  made  into  a  briquette  of  one 
inch  square  cross  section,  and  given  one  hour  in  air  and  twenty-three 
hours  in  water,  it  will  sustain  a  tensile  strain  of  250  Ibs.  before  frac- 
ture. It  can  be  produced  in  this  country  in  colors  ranging  from 
black  to  snowy  white,  and  by  the  admixture  of  the  various  shades  of 
sand  or  clay  very  pleasing  effects  can  be  produced. 

There  are  immense  deposits  of  gypsum  in  this  country,  notably 
in  the  States  of  New  York,  Virginia,  Ohio,  Michigan,  Iowa,  Kansas, 
Arizona,  California,  Texas,  Colorado,  and  Utah. 

The  production  from  the  various  deposits  amounts  to  about 
255,000  tons  yearly.  Approximately,  63  per  cent,  of  this  amount  is 
calcined  into  plaster  of  Paris,  and  37  per  cent,  is  ground  and  used  as 
a  fertilizer. 

The  importation  of  gypsum  rock  amounts  to  about  1 84,000  tons 
yearly.  Could  some  cheap  and  effectual  process  be  found  to  render 
this  material  practically  frost-proof,  its  use  in  exterior  ornamentation 
would  rapidly  assume  immense  proportions,  and  its  value  as  a  build- 
ing material  would  be  almost  incalculable. 


54  AMERICAN    CEMENTS. 


CHAPTER   VI. 

THE  CHEMISTRY  OF  CEMENTS  —  OPINIONS  OF  LEADING  AUTHOR- 
ITIES —  PRACTICAL  EXPERIMENTS  TO  DEMONSTRATE  THE 
TRUTH  OR  FALSITY  OF  VARIOUS  THEORIES  —  RELATIVE 
VALUES  OF  LIMESTONES  AND  MAGNESIAN  LIMESTONES  AS  A 
FLUX — COMBINING  RATIOS  OF  THE  VARIOUS  SILICATES  — 
ANALYZATION  OF  ANALYSES  —  MAGNESIAN  CEMENTS  — 
TABLE  OF  ATOMIC  WEIGHTS  —  METHOD  OF  CALCULATING 
CHEMICAL  COMBINATIONS  IN  CEMENTS  —  ADULTERATION  OF 
ARTIFICIAL  CEMENTS  —  EFFECT  OF  INCREASING  THE  PER- 
CENTAGE OF  LIME  —  BECOMES  BRITTLE  WITH  AGE  —  THE 
TOUGHNESS  OF  ROCK  CEMENTS  ABSENT  IN  THE  ARTIFICAL 
PRODUCT. 

The  question  has  often  arisen  and  has  been  discussed  with  a 
greater  or  less  degree  of  intelligence  by  writers  during  the  past  half 
century  concerning  the  effects  of  the  presence  of  magnesia  in  a 
cement. 

The  opinions  are  so  various  and  contradictory  as  to  lead  to  the 
suspicion  that  very  little  is  known  about  the  subject, —  a  conclusion 
difficult  to  disprove  if  investigation  be  confined  to  the  purely  hypo- 
thetical theories  advanced. 

It  may  be  stated,  however,  that  at  the  present  time  the  prevailing 
opinion  is  that,  while  magnesia  may  not  be  harmful  in  a  natural 
cement,  even  though  present  to  the  extent  of  20  per  cent,  of  the 
total,  yet  more  than  3  per  cent,  of  the  same  material  is  dangerous  in 
an  artificial  cement. 

This  is  the  position  taken  by  many  leading  authorities  on  the 
subject.  .  Others,  however,  qualify  this  statement,  or,  failing  to  deter- 
mine the  question,  leave  the  subject  in  doubt  and  obscurity ;  while 
still  others  maintain  that  magnesia  is  a  valuable  ingredient  in  a  cement. 


AMERICAN   CEMENTS.  55 

Prof.  E.  J.  De  Smedt,  in  his  annual  report  to  the  Engineer 
Department,  Washington,  D.  C,  ending  June  30,  1885,  states  in 
regard  to  the  composition  of  a  Portland  cement :  — 

"  Portland  cement  is  composed  of  bi-basic  silicate  of  lime  and 
aluminate  of  lime ;  sometimes  it  contains  small  quantities  of  magnesia 
as  silicate  or  aluminate,  some  oxide  of  iron,  alkali  in  small  quantity, 
etc.  Silicates  and  aluminates  of  lime  are  the  principal  constituents 
of  Portland  cement,  the  formulas  of  which  to  calculate  with  are  as 
follows  :  — 

2CaO.  SiO2 —  Lime 65.12 

Silicic  Acid 34.88 

100.00 

2MGO.  SiO2 —   Magnesia 57.15 

Silicic  Acid 42.85 


100.00 

CaO.  Abo3 —  Lime 67.33 

Alumina 32.67 


100.00 


"  The  magnesia  may  be  calculated  as  lime  when  found  in  small 
quantities. 

"  A  limestone,  such  as  dolomite,  containing  46  per  cent,  of 
magnesia,  has  been  pronounced  unfit  for  making  good  cement,  but 
when  the  percentage  of  magnesia  is  not  too  large  it  becomes  in  time 
just  as  hard  as  a  cement  containing  no  magnesia,  with  this  difference, 
that  it  is  somewhat  slow  in  setting.  In  sea  water  containing  mag- 
nesia such  cement  should  be  preferred,  for  the  reason  that  it  does 
not  disintegrate  in  that  water. 

"  After  careful  analyses,  calculations,  and  comparative  tests,  I 
have  found  that  the  best  results  are  obtained  when  the  relative 
quantity  of  alumina  is  in  the  proportion  of  between  one  third  and 
one  fourth  to  the  total  amount  of  alumina  and  silica  found  by  analysis. 
The  quality  of  Portland  cement  is  perfect  in  proportion  as  the  above 
formulas  are  closely  adhered  to  in  its  composition.  Sulphuric  acid 


56  AMERICAN    CEMENTS. 

in  more  than  I  per  cent,  is  detrimental,  and  a  small  percentage  of 
alkali,  such  as  soda  or  potash,  adds  very  much  to  the  virtue  of  the 
cement. 

"  Now,  it  is  not  sufficient  that  the  proportions  should  be  correct; 
it  is  also  necessary  that  calcination  should  be  at  the  proper  degree  of 
heat  and  length  of  time,  in  order  to  produce  the  formation  of  bi-basic 
silicate  of  lime  and  aluminate  of  lime." 

Prof.  S.  B.  Newberry,  a  leading  authority  on  Portland  cement  in 
this  country,  in  a  paper  prepared  for  the  United  States  Geological 
Survey  and  published  in  Mineral  Resources  of  the  United  States  for 
1892,  states:  — 

"  Late  experiments  by  Erdmenger  and  others  seem  to  prove  that 
magnesia  is  an  inert  material  in  cement  mixtures,  and  that  this  con- 
stituent does  not  combine  with  silica  and  alumina  after  the  manner  of 
lime.  The  injurious  effect  of  magnesia  in  Portland  cement  is  ascribed 
to  the  very  slow  hydration  and  expansion  of  the  free  magnesia  con- 
tained in  the  cement,  causing  cracking  of  the  mass  weeks  or  months 
after  immersion  in  water.  Magnesium  carbonate  calcined  at  low 
heat  combines  readily  with  water ;  that  which  has  been  heated  to 
the  temperature  of  the  Portland  cement  kiln  becomes  hydrated  only 
after  the  lapse  of  long  periods  of  time.  The  harmlessness  of  mag- 
nesia in  common  hydraulic  cement  is  doubtless  due  to  the  readiness 
and  completeness  with  which  it  becomes  hydrated  on  mixing  the 
cement  with  water." 

Prof.  E.  T.  Cox,  in  his  Geological  Report  for  the  State  of 
Indiana,  1878,  page  70,  says:  — 

"  For  hydraulic  purposes  the  essential  constituents  of  a  cement 
stone  are  carbonate  of  lime  and  silica.  By  calcination  the  carbonate 
of  lime  converts  the  silica  into  silicic  acid,  which  forms  a  gelatinous 
mass  with  acids.  Carbonate  of  magnesia  acts  in  a  similar  manner  to 
carbonate  of  lime,  and  when  the  two  are  present  in  the  proper  pro- 
portions hydraulic  energy  is  uninterrupted,  and  a  stone  is  formed,  of 
great  strength  and  durability,  which  consists  of  a  double  silicate  of 
lime  and  magnesia.  A  portion  of  alumina  is  not  objectionable  in  a 
cement  stone  in  the  presence  of  plenty  of  carbonate  of  lime  and  silica; 
it  enters  into  combination  as  a  hydrated  silicate  of  lime  and  alumina. 
Sulphuric  acid,  or  sulphate  of  lime,  does  not  promote  hardening  or 
setting  of  the  cement,  and  the  same  may  be  said  of  the  oxide  of  iron. 


AMERICAN    CEMENTS.  57 

Large  quantities  of  these  substances  are  therefore  objectionable,  and 
they  may  be  looked  upon  as  adulterations. 

"  Since  carbonates  of  lime  or  magnesia,  aided  by  alkalies,  when 
present,  are  the  active  agents  during  the  calcining  of  the  cement 
stone  in  bringing  about  the  decomposition  of  the  silicates  and  forming 
a  silicate  that  is  soluble  in  acids,  it  will  be  interesting  to  present  a 
tabular  arrangement  of  the  ratio  of  silica  to  the  carbonates  of  lime 
and  magnesia  in  the  above,  and  some  additional  analyses  of  cement 
stones  that  are  in  common  use  :  — 

ANALYSIS. 

SILICATES.    CARBONATRS. 

Balcony  Falls,  Va 100  149 

Rosendale,  N.  Y 100  248 

Wabash  County,  Ind 100  124 

Cumberland,  Md 100  186 

Beache's,  Clark  County,  Ind 100  262 

Vassy,  France 100  465 

English 100  341 

Bologne 100  311 

"  Between  the  silicates  and  carbonates,  including  the  carbonates 
of  lime,  magnesia,  and  alkalies,  when  present,'  there  is  a  wide  variation 
in  cement  stones  of  good  repute  for  hydraulic  energy. 

"It  has  already  been -stated  that  for  hydraulic  properties  the 
essential  constituents  of  a  cement  are  silicic  acid  and  caustic  lime. 
The  hardening  under  water  is  mainly  due  to  the  chemical  combina- 
tion of  these  two  constituents  through  the  agency  of  water,  producing 
hydrated  silicate  of  lime ;  where  other  bases  are  present,  such  as 
alumina  and  magnesia,  double  silicates  are  formed  that  become  very 
hard  and  strong.  In  order  to  bring  about  this  chemical  change  the 
silica  must  be  brought  to  that  condition  which  will  enable  it  to  form 
a  gelatinous  paste  with  acids.  A  portion  of  the  silica  may  be  in  this 
condition  naturally,  but  by  far  the  larger  portion  remains  unacted 
upon  by  acids  until  brought  to  a  white  heat  in  the  presence  of  car- 
bonate of  lime." 

Many  years  ago,  M.  Vicat,  the  famous  French  engineer,  made 
the  following  statement :  — 

"  Magnesia  is  a  valuable  ingredient  in  mortars  to  be  immersed 


58  AMERICAN    CEMENTS. 

in  sea  water,  and  if  it  could  be  obtained  at  a  cost  that  would  permit 
of  its  application  to  such  purposes  the  problem  of  making  beton 
(concrete)  unalterable  by  sea  water  would  be  solved. 

"  Without  clay,  that  is  to  say,  without  silica,  limes  cannot  be 
decidedly  hydraulic. 

"  The  different  combinations  I  have  tried,  by  mixing  chalk  and 
magnesia,  have  only  produced  limes  susceptible  of  setting  in  the 
commencement,  without  any  ulterior  progress ;  but  this  solidification, 
imperfect  though  it  be,  denotes  in  the  magnesia  certain  hydraulic 
properties  which  the  alumina  itself  does  not  possess. 

"  If,  then,  some  portions  of  clay  be  present,  it  might  happen  that 
a  triple  hydrate  of  lime,  of  alumina,  and  of  magnesia  might  be  formed 
which  should  possess  all  the  conditions  of  hardness  and  of  progres- 
sion which  characterize  the  best  hydraulic  limes. 

"  Two  species  of  limestones  which  were  found  to  contain 
respectively,  before  burning,  as  follows,  viz. :  — 

Clay 4.00  and  5.50 

Carbonate  of  lime 42.50     „    52.00 

„  „    magnesia 53-5°     ?>    42.50 

yielded  limes  possessing  the  hydraulic  character  in  an  eminent 
degree." 

M.  Parandier  stated  that  "  a  stone  composed  of  58  parts  of  car- 
bonate of  lime,  1 1  of  clay,  and  31  of  carbonate  of  magnesia  yields  a 
very  excellent  hydraulic  lime.'* 

M.  Dumas  states  that  "if  more  than  10  per  cent,  of  magnesia 
be  present,  hydraulic  limes  begin  to  become  poor,  and  with  25  per 
cent,  they  become  decidedly  poor." 

M.  Berthier  gives  the  analysis  of  a  hydraulic  lime  obtained 
from  a  mixture  of  the  stone  of  Villefranche,  near  Paris,  with  dissolved 
silica,  in  the  proportions  of  5  of  the  stone  to  i  of  the  silica. 

The  analysis  of  the  stone  being  :  — 

Carbonate  of  lime 60.90 

„           „    magnesia .  30.10 

„           „   iron    .     .     ...     .     .     .     .     .     .     .  3.00 

„           „   manganese 6.00 


Total    ,  .  100.00 


AMERICAN    CEMENTS.  59 

and    the  hydraulic  lime  thus  obtained  became  much  harder  under 
water  than  any  even  of  the  natural  hydraulic  limes. 

This  mixture   after  calcination  would  exhibit  by   analysis  the 
following  :  — 

Silica 25.83 

Lime 44-Q4 

Magnesia 18.50 

Oxide  of  iron 3.88 

„       „  manganese 7.75 


Total 100.00 

And,  as  it  contains  the  ingredients  in  proportions  essential  to  a 
good  hydraulic  cement,  it  is  not  surprising  that  it  became  "  harder 
under  water  than  any  even  of  the  natural  hydraulic  limes." 

Again,  "  when  the  magnesian  limestones  found  nearer  Paris  are 
mixed  with  one  fifth  of  their  bulk  of  soluble  siliceous  matter  they 
yield  a  lime  still  more  energetic  in  its  hydraulic  properties  than  that 
above  described,  although  the  carbonate  of  magnesia  is  present  in 
the  proportion  of  23  per  cent." 

Gen.  Q.  A.  Gillmore  in  his  "  Treatise  on  Limes,  Hydraulic  Cements, 
and  Mortars,"  ed.  1879.  page  304,  says :  "Magnesia  plays  an  im- 
portant part  in  the  setting  of  mortars  derived  from  the  argillo-mag- 
nesian  limestones,  such  as  those  which  furnish  the  Rosendale 
cements.  The  magnesia,  like  the  lime,  appears  in  the  form  of  the 
carbonate  (MgO.  CO2).  During  calcination  the  carbonic  acid  (CO2) 
is  driven  off,  leaving  protoxide  of  magnesia  (MgO.)  which  comports 
itself  like  lime  in  the  presence  of  silica  and  alumina,  by  forming 
silicate  of  magnesia  (SiO3,  3MgO)and  aluminate  of  magnesia  (A12O3. 
3  MgO).  These  compounds  become  hydrated  in  the  presence  of 
water,  and  are  pronounced  by  both  Vicat  and  Chatoney  to  furnish 
gangs  which  resist  the  dissolving  action  of  sea  water  better  than 
the  silicate  and  aluminate  of  lime.  This  statement  is  doubtless 
correct,  for  we  know  that  all  of  those  compounds,  whether  in  air 
or  water,  absorb  carbonic  acid  and  pass  to  the  condition  of  sub- 
carbonates,  and  that  the  carbonate  of  lime  is  more  soluble  in  water 
holding  carbonic  acid  and  certain  organic  acids  of  the  soil  in  solution 
than  carbonate  of  magnesia. 


60  AMERICAN    CEMENTS. 

"  At  all  events,  whatever  may  be  the  cause  of  the  superiority,  it  is 
pretty  well  established  by  experience  that  the  cements  derived  from 
the  argillo-magnesian  limestones  furnish  a  durable  cement  for  con- 
structions in  the  sea." 

G.  R.  Burnell,  C.  E.,  of  London,  in  his  work  on  "  Limes, 
Cements,  and  Mortars,"  1868,  page  17,  makes  the  following  remark- 
able statement :  — 

"In  the  actual  state  of  our  chemical  knowledge,  it  is  impossible 
to  say  whether  there  exist  any  definite  proportions  either  of  silica 
alone,  of  silica  and  alumina,  or  of  silica  and  magnesia,  etc.,  which 
are  capable,  when  mixed  with  the  same  quantity  of  pure  lime,  of 
producing  hydraulic  limes  of  similar  qualities.  Indeed,  the  whole  of 
this  branch  of  chemistry,  notwithstanding  the  important  discoveries 
made  in  it  of  late  years,  is  still  very  little  understood. 

"  The  action  of  the  oxide  of  iron,  for  instance,  quite  escapes  the 
attempts  made  to  include  it  within  any  law.  The  action  of  the  mag- 
nesia seems  also  involved  in  the  same  obscurity." 

This  being  the  true  "  state  of  the  art  "  as  late  in  the  history  of 
cements  as  1868,  it  is  not  difficult  to  understand  and  appreciate  the 
conflicting  opinions  of  the  leading  authorities  rendered  prior  to  the 
date  named,  as  well  as  those  expressed  subsequently,  and  it  may 
truthfully  be  said  that  even  at  the  present  time  the  art  of  cement 
fabrication  is  but  little  understood.  In  fact,  but  a  slight  and  scarcely 
visible  abrasion  has  been  made  on  the  surface  of  the  subject,  and, 
considering  the  limited  number  of  scientists  who  take  any  special 
interest  in  the  subject,  it  may  safely  be  predicted  that  any  advance 
in  the  art  is  destined  to  be  of  slow  growth ;  and  that  many  years  will 
have  elapsed  before  it  can  truthfully  be  claimed  that  the  chemistry 
of  cements  is  at  last  freed  from  the  fetters  of  tradition  and  rests 
securely  on  a  solid  and  permanent  foundation. 

And  when  it  is  considered  how  vastly  important  the  subject  is, 
in  view  of  the  fact  that  over  30^000,000  barrels  of  cement  enter 
yearly  into  the  works  of  construction  in  Europe  and  America,  it  is  to 
be  regretted  that  our  universities  and  institutes  of  technology  do 
not  embrace  in  their  curriculums  a  systematic  study  of  the  chemistry 
of  cements. 

So  largely  does  this  material  enter  into  the  construction  of  all 
engineering  and  architectural  works,  and  so  rapidly  does  the  field  for 


AMERICAN    CEMENTS.  61 

its  use  widen,  that  it  is  becoming  a  necessity  that  this  subject  should 
receive  the  attention  its  importance  merits. 

As  already  stated,  the  discussion  concerning  the  effects  of  the 
presence  of  magnesia  in  a  cement  has  extended  over  a  long  period 
of  years,  and,  unfortunately,  many  conclusions  have  been  drawn 
which  are  purely  hypothetical,  and,  lacking  in  practical  proof,  are  not 
only  useless,  but,  by  being  misleading,  become  harmful.  An  error  of 
this  character  is  afforded  in  the  passage  quoted  from  Gillmore. 

Silicates  are  not  decomposed  in  the  manner  stated.  The  only 
portion  of  a  cement  that  could  be  thus  acted  upon  by  carbonic  acid 
is  the  lime  and  magnesia  that  may  be  in  excess  of  true  combining 
proportions  with  the  silica  present. 

Practical  experience  has  demonstrated  that  any  cement  which 
contains  an  excess  of  either  lime  or  magnesia,  if  not  thoroughly 
hydrated  prior  to  its  application,  is  attended  with  the  danger  of 
expansion.  And  any  cement  deficient  in  these  bases  is  subject  to 
shrinkage.  An  excess  of  lime  in  a  cement,  whether  natural  or 
artificial,  without  thorough  hydration,  as  already  stated,  will  surely 
expand  to  a  greater  or  less  extent.  And,  as  the  process  of  hydra- 
tion as  usually  practised  consists  in  the  mere  spreading  of  the 
manufactured  cement  on  a  floor  and  by  repeated  turnings  with 
shovels,  exposing  the  body  of  the  cement  to  the  atmosphere,  the 
caustic  lime  takes  up  the  moisture  in  the  air,  and  produces  a  hydrate 
of  lime  which  is  thereby  rendered  non-expansive.  And  its  influence 
on  the  resultant  mortar  is  the  same  as  when  a  given  percentage  of 
thoroughly  slaked  quicklime  is  added  to  a  harsh  or  quick  setting 
cement,  rendering  it  less  active  and  imparting  a  pasty  consistency  to 
the  mortar.  An  excess  of  lime  in  a  cement,  whether  inherent  in  the 
cement  or  added  subsequently,  if  the  hydration  has  been  conducted 
thoroughly  and  conscientiously,  cannot  be  considered  as  harmful ;  on 
the  contrary,  it  may  be,  on  the  whole,  beneficial.  The  only  danger 
attending  its  use  arises  from  the  extreme  liability  of  an  imperfect 
hydration. 

The  often  expressed  opinion  that  any  excess  of  lime  or  magne- 
sia will  ultimately  dissolve  out  of  the  masonry,  leaving  the  mortar 
porous,  and  thereby  lead  to  disintegration,  is  not  borne  out  by  the 
facts.  Teil  hydraulic  lime,  containing  thirty-four  to  forty  per  cent, 
of  free  lime,  has  been  used  in  enormous  quantities  for  centuries,  and 


62  AMERICAN   CEMENTS. 

certainly  in  sea  water  since  1832,  and  the  free  lime  which  it  contains 
shows  no  signs  of  dissolving  out,  whether  used  in  air  or  water. 

In  the  manufacture  of  artificial  cements,  which  invariably 
contain  an  excess  of  lime,  the  question  of  thorough  hydration 
presents  in  the  case  of  large  and  extensive  works  quite  a  serious 
problem,  one  which  enters  quite  seriously  into  the  cost  of  manufac- 
ture. 

The  large  floor  space  necessary  for  the  purpose  and  the  time 
required  for  thorough  hydration,  the  large  stock  to  be  carried  and 
the  labor  involved  in  turning,  enter  into  the  cost  of  production, 
and,  as  in  these  days  of  close  and  severe  competition  the  strictest 
economy  in  manufacture  becomes  imperative,  it  is  evident  that 
the  process  of  hydration  is  oftentimes  hurried  and  imperfectly 
done. 

The  author  has  never,  in  a  long  series  of  trials,  been  able  to  find 
an  artificial  cement  of  foreign  or  domestic  production  which,  when 
made  into  grout  and  poured  into  bottles,  would  not  sooner  or  later 
fracture  every  bottle. 

The  only  significance  to  be  attached  to  these  trials  consists  in 
the  fact  that  none  of  the  brands  tried  contained  magnesia  in  excess 
of  the  empiric  limit  of  three  per  cent. 

The  expansion,  therefore,  could  not  be  charged  to  that  source, 
and  the  only  conclusion  to  be  drawn  was  that  the  process  of  hydra- 
tion had  been  improperly  conducted,  and  caustic  lime  had  been  per- 
mitted to  remain  in  the  cement  when  packed  for  the  market. 

Neither  lime  nor  magnesia  will  expand  in  a  cement  if  combined 
with  silicic  acid  or  when  in  a  free  and  uncombined  condition,  if 
thoroughly  hydrated. 

There  are  no  known  cements  which  would  be  damaged  in 
quality  should  they  contain  magnesia  up  to  the  combining  limit. 

We  have  shown  that  magnesia  combines  with  silica  in  certain 
fixed  proportions,  and  that  when  lime  enters  into  the  composition 
the  proportions  as  between  silica  and  magnesia  are  changed,  but  in 
either  case  the  proportions  are  fixed  and  constant.  A  true  silicate  of 
magnesia  will  attain  a  hardness  equal,  if  not  superior,  to  that  of  sili- 
cate of  lime. 

The  former  contains  a  larger  percentage  of  silica,  as  will  be 
seen  from  the  following  table. 


AMERICAN  CEMENTS.  63 

Silicate  of  Magnesia.  Silicate  of  Lime. 

Silica,         42.92  Silica,  34.91 

Magnesia,  57.08  Lime,  65.09 


Totals        100.00  100.00 

If  there  is  any  advantage  in  the  inherent  hardness  of  the  con- 
stituent parts  considered  separately,  the  advantage  would  seem  to  be 
in  favor  of  the  silicate  of  magnesia,  as  silica  is  harder  than  either  of 
the  bases  named,  and,  while  it  requires  but  760  parts  of  water  to  dis- 
solve one  part  of  lime,  magnesia  is  practically  insoluble  in  water. 

An  illustration  is  afforded  in  the  large  number  of  shell-marl  beds 
found  in  many  portions  of  this  country  (nearly  all  of  which  are 
formed  by  animal  secretion  in  the  waters  of  former  lakes  or  ponds). 
Although  the  surrounding  or  adjacent  rocks  are  in  most  instances 
magnesian  limestones,  from  which  by  infiltration  the  ponds  became 
supplied  with  calcium  carbonate  in  solution,  and  from  which  the 
shells  were  secreted,  it  is  very  rarely  that  the  shells  are  found  to  con- 
tain even  three  per  cent,  of  magnesium  carbonate  —  being  practically 
pure  calcium  carbonate. 

Several  years  ago,  the  author,  in  searching  for  a  reason  for  this 
general  belief  in  the  dangerous  qualities  of  magnesia  in  a  cement 
when  exceeding  the  time-honored  limit  of  three  per  cent.,  instituted  a 
series  of  experiments. 

Magnesian  limestones  were  secured  which  varied  in  their  pro- 
portions of  carbonate  of  magnesia  from  five  to  fifteen  per  cent. 
These  were  marked  and  treated  separately,  by  grinding  the  samples 
to  impalpable  powder,  to  which  was  added  clay  in  an  equally  fine 
condition,  in  such  proportions  as  are  prescribed  as  the  correct  for- 
mulae for  Portland  cements,  and,  after  a  thorough  admixture  of  these 
ingredients,  the  samples  were  moistened  and  formed  into  balls  and 
cakes,  which  were  then  calcined  with  coke  to  the  point  of  incipient 
vitrifaction,  after  which  the  samples  were  finely  pulverized,  the 
powder  thoroughly  hydrated,  formed  into  patties,  balls,  and  bri- 
quettes, and  given  the  usual  time  in  air  and  water. 

The  tests  extended  from  one  day  to  one  year.  The  weight  and 
tests  were  fully  up  to  the  standard  for  the  best  artificial  cements. 
Some  of  the  samples  are  now  nine  years  old  ;  they  have  been  kept  in 


64  AMERICAN    CEMENTS. 

both  fresh  and  salt  water,  and  they  show  no  signs  of  expansion  or 
checking,  and  are  exceedingly  hard. 

Following  in  this  line  to  determine  if  it  were  possible  that  a 
good  cement  could  be  produced,  should  the  lime  be  replaced  entirely 
by  magnesia,  many  experiments  were  conducted  with  various  sub- 
stances known  as  silicates  of  magnesia,  with  varying  success,  until  a 
trial  of  serpentine  (Mg3  Si2  O7  -f  2H2  O)  was  reached. 

In  the  experiments  with  this  material  much  difficulty  was  ex- 
perienced, owing  to  the  varying  qualities  of  this  rock.  It  was  found 
that  verd-antique,  a  mixture  of  serpentine  and  calcium  carbonate, 
and  many  samples  mottled  or  otherwise  not  uniform  in  color  or 
texture  gave  results  that  were  not  entirely  satisfactory.  But  the 
dark  green  varieties  which  were  uniform  in  color  and  fine  in  texture 
gave  results  that  were  most  surprising. 

Samples  of  this  class  from  near  Philadelphia,  Penn.,  near  New 
Haven,  Conn.,  and  Marquette,  Mich.,  yielded  an  hydraulic  cement 
that  equaled  in  hardness  and  toughness  the  best  natural  or  artificial 
cements. 

In  the  calcination  of  this  cement  the  heat  required  is  not  so 
great  as  that  necessary  for  ordinary  cements.  With  the  latter  the 
heat  must  be  high  enough  to  at  least  expel  the  carbon  dioxide  from 
the  carbonates,  which  requires  above  2700°  Fahr.,  while  serpentine, 
which  has  parted  with  its  carbon  dioxide  through  metamorphic 
action,  requires  a  heat  but  little  above  that  necessary  to  expel  the 
water  of  crystallization  to  render  it  suitable  for  grinding,  after  which 
it  becomes  practically  an  hydraulic  cement. 

The  samples  tested  were  slow  in  setting,  requiring  one  day  in 
air  before  submersion.  Neither  shrinkage  nor  expansion  was 
detected.  Samples  of  this  cement  have  now  been  kept  in  both  fresh 
and  sea  water  for  seven  years,  and,  except  by  analysis,  they  can- 
not be  recognized  as  other  than  ordinary  cement  of  the  finest 
quality. 

The  theory  that  more  than  3  per  cent,  of  magnesia  is  harmful  in 
an  artifical  cement  has  not  been  sustained,  except  by  the  single 
argument  that  it  remains  free  or  uncombined  in  the  cement,  and, 
owing  to  the  high  temperature  to  which  that  cement  is  subjected 
during  calcination,  slowly  hydrates,  and  expands  after  the  lapse  of 
many  days  and,  perhaps,  months. 


OF 

_  UNIVERSITY 

AMERICAN    CEM\NTS.  J         65 


Whenever  it  can  be  shown  that  magnesia  does  not  combine  with 
the  silica,  then  the  truth  of  the  theory  will  have  to  be  admitted. 

But  to  establish  the  theory  as  a  fact  it  must  first  be  shown  that 
silica  and  magnesia  do  not  combine,  as  in  Serpentine  (Mg3  Si2O7  +2 
H2O),  Talc  (Si5  O14  Mg4),  Sepiolite  (Si3  O8  Mg2+2  H2  O),  or  in 
Olivine(Mg2  Si  O4),  and  among  the  silicates  of  magnesia  and  lime, 
as  in  asbestos,  the  augites,  hornblendes,  and  pyroxene. 

How  can  these  be  admitted  as  chemical  combinations  of  silica, 
lime,and  magnesia,without  admitting  a  similar  combination  in  cements  ? 

The  theory  has  not  the  slightest  foundation,  in  fact.  Its 
absurdity  has  been  demonstrated  daily  since  the  foundation  of  the 
cement  industry  in  this  country. 

But  in  an  endeavor  to  account  for  the  expansion  of  some  of  the 
artifical  cements,  this  theory  has  been  advanced  by  many  leading 
authorities,  principally  in  Germany,  who,  it  may  be  noted,  have  never 
advertised  for  an  adverse  opinion,  and  among  the  imitators  of  those 
authorities  in  this  country  the  theory  has  passed  current  as  sound 
doctrine.  But  the  untenableness  of  this  doctrine  seems  not  to  have 
occurred  to  its  advocates,  even  when  they  find  checking  and  expansion 
taking  place  among  artificial  cements  containing  but  a  trace  of 
magnesia. 

When  a  cement  containing  an  excess  of  lime  has  been  calcined 
at  an  extreme  high  temperature,  the  free  lime  will  be  much  slower  to 
hydrate  than  would  be  the  case  were  the  cement  calcined  at  a  lower 
temperature,  and  herein  may  be  found  the  reason  for  checking,  which, 
to  account  for,  has  been  attributed  to  the  presence  of  magnesia. 

As  instances  of  this  character,  the  foundation  of  the  Bartholdi 
statue  in  New  York  Harbor  may  be  cited.  After  this  work  had  been 
laid  several  months,  the  surface  became  covered  with  innumerable 
checks  and  cracks. 

The  landing  of  the  main  entrance  of  the  Capitol  Building, 
Washington,  D.  C.,  fronting  Pennsylvania  Avenue,  was  so  literally 
covered  with  checks  and  cracks  that  a  dime  dropped  upon  it  would 
rest  on  a  check  or  crack,  and  it  was  found  necessary  to  cover  it  with 
asphalt. 

Both  of  the  cases  cited  were  done  with  a  German  Portland 
cement  having  a  reputation  second  to  none  in  this  country,  and  the 
analysis  of  which  shows  but  a  trace  of  magnesia. 


66  AMERICAN    CEMENTS. 

The  only  conclusion,  therefore,  to  be  drawn  is  that  the  checking 
resulted  from  a  lack  of  thorough  hydration  of  the  lime  that  was 
present  in  excess  of  true  combining  proportions. 

Had  American  rock  cement  been  used  in  the  work  cited,  and 
had  the  same  results  followed,  it  is  extremely  probable  that  the 
engineer  and  contractor  would  have  been  censured  for  not  having 
used  Portland  cement. 

The  question  of  hydration  is  one  which  demands  careful  con- 
sideration. It  is  a  question  which  rarely  enters  into  the  calculations 
of  engineers  and  architects,  who  rely  almost  wholly  on  short  time 
tensile  tests,  which  rarely  extend  beyond  thirty  days. 

A  cement  which  needs  hydration  will,  when  this  operation  is 
but  partially  effected,  test  higher  during  the  time  mentioned  than 
when  thoroughly  hydrated.  Yet  at  the  end  of  six  months  or  a  year 
the  benefits  of  thorough  hydration  will  appear  in  the  tests. 

These  results  follow,  whether  the  cement  contains  more  or  less 
magnesia,  not  in  excess  of  its  true  combining  proportions. 

The  author  has  had  a  practical  experience  of  many  years  with 
the  cement  which  is  represented  in  the  table  of  analyses  as  No.  29,  by 
which  it  may  be  seen  that  it  contains  a  large  percentage  of  magnesia. 

The  rock  from  which  this  cement  is  produced,  when  calcined, 
at  the  temperature  employed  in  Portland  cement  making,  /.  *?.,  sin- 
tered, then  ground  and  hydrated,  will  weigh,  without  compacting,  85 
Ibs.  per  cube  foot,  which  is  equivalent  to  106  Ibs.  per  struck  bushel. 

It  will  test  100  Ibs.  tensile  strain  per  square  inch  atone  day, 
250  Ibs.  at  seven  days,  400  Ibs.  at  one  month,  700  Ibs.  at  six  months, 
and  at  one  year  a  major  portion  of  the  briquettes  cannot  be  broken 
on  a  1,000  Ib.  testing  machine. 

Commencing  in  1883,  and  continued  yearly  since  that  time 
until  the  present,  briquettes  made  from  this  material  have  been 
placed  in  running  water,  and  kept  there,  and  they  neither  expand, 
check,  nor  shrink,  but  are  infinitely  harder  than  the  rock  from  which 
they  were  produced. 

The  motive  for  presenting  this  particular  instance  is  because  of 
its  direct  bearing  on  the  question  of  the  presence  and  influence  of 
magnesia  in  a  cement. 

Practical  experiences  of  this  kind  completely  dispose  of  many  of 
the  fallacies  by  which  the  consideration  of  this  subject  is  complicated. 


AMERICAN    CEMENTS.  67 

If  the  tendency  to  expand  is  greater  in  magnesia  than  in  lime, 
it  ought  to  exhibit  such  tendency  in  the  common  building  lime.  Of 
the  more  than  sixty  millions  of  barrels  of  this  material  which  is 
produced  yearly  in  this  country,  not  less  than  two  thirds  of  it  is 
produced  from  magnesian  limestone,  the  proportion  of  magnesia 
ranging  from  10  per  cent,  up  to  a  percentage  rendering  the  material 
dolomitic  in  character. 

The  heat  required  for  the  calcination  of  this  rock  is  fully  as 
high  as  that  used  in  the  production  of  Portland  cement. 

It  is  generally  used  immediately  after  slaking.  Yet  it  does  not 
expand  and  rupture  brickwork  and  stone  masonry,  although  the 
magnesia  is  absolutely  free.  It  is  not  chemically  combined  with  the 
lime  ;  neither  does  it  so  combine  subsequently  with  the  gangue  with 
which  it  is  made  into  mortar  or  concrete,  its  deportment  being 
the  same  as  that  of  the  lime  with  which  it  is  associated. 

If  magnesia  does  not  expand  in  work  where  it  is  beyond  all 
question  in  a  free  or  uncombined  condition,  it  certainly  cannot  do 
so  when  it  is  converted  into  silicates,  as  in  an  hydraulic  cement, 
whether  the  latter  is  a  natural  or  artificial  product. 

Evidence  of  a  most  conclusive  character  bearing  on  this  ques- 
tion of  the  formation  of  magnesian  silicates  in  a  cement,  whether 
natural  or  artifical,  is  furnished  in  the  carefully  ascertained  values  of 
the  various  limestones  and  magnesian  limestones  when  used  as  a  flux 
in  the  smelling  of  iron  ores. 

It  is  familiarly  known  that  the  silica  contained  in  iron  ores  is 
removed  by  combining  it  with  lime,  or  lime  and  magnesia  (depend- 
ent on  the  character  of  the  stone  used),  the  resultant  product  being 
a  silicate  of  those  bases  in  the  form  of  clinker  or  slag. 

The  value  of  this  fluxing  material  is  measured  by  its  capacity 
for  taking  up  the  silica  contained  in  the  ore. 

It  is  evident,  therefore,  that  these  values  diminish  in  direct  ratio 
with  the  increase  in  the  percentages  of  silica,  clay,  and  other 
impurities  contained  in  the  stone. 

Thus  we  find  that  if  a  magnesian  limestone  contains  1 5  per  cent, 
of  impurities,  1 2  parts  of  which  are  silica,  as  in  No.  8  of  the  follow- 
ing table,  the  fluxing  value  of  the  stone  falls  to  less  than  one  half 
the  value  of  that  of  a  practically  pure  magnesian  limestone,  like 
No.  i  in  the  table. 


68 


AMERICAN    CEMENTS. 


This  decrease  in  values  is  due  to  the  silica  found  in  the  stone, 
which  takes  up  its  equivalent  of  lime  and  magnesia,  leaving  only 
the  excess  of  those  bases  to  combine  with  the  silica  in  the  ore. 

A  study  of  the  table,  \vhich  is  compiled  with  unusual  care  and 
exactness,  should  serve  to  dissipate  all  doubt,  and  place  beyond 
further  controversy  the  evident  fact  that  magnesia  combines  with 
silica,  and  when  for  that  purpose,  it  is  used  as  a  flux,  it  has  even  a 
greater  value  than  lime. 

In  all  respects  the  law  holds  good  in  the  fabrication  of  hydraulic 
cements,  as  the  clinker  or  slag  from  smelting  furnaces  is  simply  an 
unground  hydraulic  cement. 

Should  the  stone  used  be  of  an  impure  variety,  the  resultant 
slag  is  a  mixture  of  natural  and  artificial  hydraulic  cement,  although 
of  such  varying  proportions  as  between  the  acid  and  the  bases  as  to 
be  practically  valueless  for  that  purpose. 

Nevertheless,  it  is  largely  used  as  an  adulterant  by  unscrupulous 
European  manufacturers  of  artificial  cements. 

If  we  are  to  believe  the  printed  reports  of  the  transactions  of 
the  societies  of  English,  German,  and  Belgian  Portland  cement  manu- 
facturers, it  would  seem  that  those  organizations  are  utterly  power- 
less to  suppress  the  dishonest  practises  of  many  of  their  members. 

TABLE    OF   RELATIVE   VALUES    OF    LIMESTONES    AND    MAGNESIAN 

LIMESTONES   AS   A   FLUX. 
(Nos.  2,  4,  7,  and  10  Limestones,     i,  3,  5,  6,  8,  and  9,  Magnesian  Limestones.) 


No. 

Lime. 

Magnesia. 

Carbon 
dioxide. 

Silica. 

Alumina 
oxide  of 

Totals. 

Flux 

Totals. 

Flux 
Values. 

iron,  etc. 

i 

37.00 

1  6.  oo 

46.68 

0.32 

100 

53-o° 

1.  000 

2 

56.00 

44.00 

ioo 

56.00 

•937 

3 

45.00 

8.00 

44.17 

1.  00 

i'.83 

IOO 

53.00 

.922 

4 

53.00 

41.66 

3-oo 

2-34 

TOO 

53  oo 

•797 

5 
6 

36.00 
44.00 

16.00 
8.00 

45.89 
43-38 

2.OO 
2.00 

O.I  I 

2.62 

100 
100 

52.00 
52.00 

.906 
.828 

7 

152.00 

40.87 

4.00 

3-'3 

IOO 

52.00 

•750 

8 

31.00 

14.00 

39-76 

12.00 

3-24 

IOO 

45.00 

.484 

9 

39.00 

6.00 

37-25 

J2.00 

5-75 

IOO 

45.00 

.406 

JO 

.  45.00 

35-37 

15.00 

4-63 

IOO 

45.00 

.219 

The  question  of  the  presence  of  alumina  in  a  cement,  its  action 
and  influence  on  the  quality,  and  its  mode  of  combination,  has  also 
been  the  source  of  much  discussion  by  the  authorities.  The  presence 
of  alumina  is  due  to  the  fact  that  silica,  without  which  hydraulic 


AMERICAN    CEMENTS.  69 

cement  has  not  been  produced,  is  not  found  in  quantities  sufficiently 
fine  except  in  combination  with  alumina,  /.  e.,  in  clay.  And  so  it 
may  be  said  to  be  an  unwelcome  accompaniment  to  silica  in  the 
composition  of  an  artificial  cement,  while  in  natural  cement  it  is 
inherent  in  the  cement  rock,  being  combined  with  the  silica. 

It  is  both  basic  and  acidic  in  its  character.  In  its  combination 
with  silica,  as  in  clay,  its  action  is  purely  that  of  a  base.  In  this 
condition  of  silicate  of  alumina  it  is  not  decomposed  by  heat,  as  is 
demonstrated  in  the  production  of  fire-brick  from  that  material. 

Taken  in  a  pure  state,  alumina  will  combine  with  lime,  forming 
alummate  of  lime,  thus  proving  its  acidic  character. 

Its  combining  proportions  with  silica  and  lime,  considered 
separately,  are  as  follows  : 

Silica         63.83  Alumina     32.67 

Alumina   36.17  Lime  67.33 

Totals     100.00  100.00 

The  author  has  been  furnished  some  beautiful  specimens  of 
aluminate  of  lime  by  Prof.  S.  B.  Newberry,  who  produced  them  in. 
his  laboratory,  and  states  that  "  they  were  practically  fused  at  a 
bright  yellow  heat.  A  low  temperature  compared  with  that  required 
to  produce  Portland  cement." 

The  basic  character  of  alumina  exceeds  the  acidic,  but  it  is  so 
feeble  that  it  is  not  capable  of  forming  salts  with  weak  acids,  while 
its  acidic  character  is  also  feeble  and  can  only  form  compounds  with 
strong  bases. 

These  peculiar  characteristics  of  alumina  have  led  to  a  variety 
of  opinions  concerning  its  true  position  in  an  hydraulic  cement  com- 
position. 

Many  excellent  authorities  assert  that  in  a  cement  both  silicate 
and  aluminate  of  lime  are  formed.  While  others  maintain  that 
silica  combines  with  both  bases,  lime  and  alumina,  forming  bi-silicate 
of  lime  and  alumina. 

Some  of  the  advocates  of  each  of  these  theories  claim  that 
magnesia,  if  present,  remains  inert  in  the  cement,  that  is,  free  and 
uncombined.  While  others  maintain  that  it  combines  only  with  the 
silica  and  lime ;  while  still  others  maintain  that  it  combines  with  the 
silica,  lime,  and  alumina,  forming  a  triple  silicate. 


70  AMERICAN    CEMENTS. 

It  has  also  been  stated  by  some  eminent  chemists  that  after  cal- 
cination all  the  constituents,  silica,  alumina,  lime,  and  magnesia,  are 
in  a  free  condition,  and  that  it  is  only  by  the  application  of  water 
that  silicates  are  formed,  some  claiming  that  silicate  of  lime  and 
aluminate  of  lime  are  thus  formed  ;  and  by  others  that  by  the  ap- 
plication of  water  the  silica  combines  with  all  the  bases  present  in 
certain  fixed  proportions;  but  in  neither  of  these  last  two  mentioned 
cases  is  it  admitted  that  water  combines  with  and  causes  the  crys- 
tallization of  silicates  already  formed  by  the  agency  of  heat. 

While  the  analytical  side  of  the  cement  question  seems  to  be 
fairly  well  understood,  it  is  apparent  that  the  synthetical  side  has 
been  neglected. 

That  neither  magnesia  nor  alumina  is  absolutely  essential  to 
the  fabrication  of  an  hydraulic  cement  has  been  well  demonstrated ; 
but  each  is  present,  in  greater  or  less  proportion,  in  all  cements,  and 
it  is  interesting  to  note  the  theories  advanced  by  our  leading 
authorities  in  regard  to  the  perplexing  problems  attending  the  pres- 
ence of  these  two  bases  and  their  mode  of  combination. 

The  views  of  Prof.  DeSmedt  on  this  question,  also  those  of 
Prof.  Cox,  are  clearly  expressed  in  the  quotations  already  given, 
from  their  writings. 

Leonard  F.  Beckwith,  C.  E.,  New  York,  in  his  report  on  the 
"  Hydraulic  Lime  of  Teil,"  page  23,  says :  "  The  method  of  manu- 
facture strongly  influences  the  composition  of  limes  and  cements. 
At  a  high  temperature,  silicate  of  lime  and  the  double  silicate  of 
lime  and  alumina  are  formed.  At  a  low  heat,  the  double  silicate  is 
not  formed,  and  the  alumina,  acting  towards  the  lime  the  part  of  an 
acid,  produces  aluminate  of  lime,"  and  that  "  the  latter  is  weak  and 
the  first  element  to  become  decomposed  in  sea-water." 

Henry  Reid,  C.  E.,  London,  in  his  work  on  "  Portland  Cements," 
ed.  1877,  page  151,  says:  "Alumina,  when  in  excess  in  a  clay,  im- 
pairs the  indurating  value  of  the  cement  in  the  making  of  which  it 
is  used.  Aluminate  of  lime  possesses  excellent  hydraulic  properties, 
but  the  temperature  necessary  for  its  formation  is  much  higher  than 
that  at  which  silicate  of  lime  is  produced. 

"  If,  therefore,  a  clay  contains  an  excess  of  alumina,  part  of  the 
silicate  of  lime  will  be  overburnt  before  the  whole  of  the  alumina 
can  enter  into  combination  with  the  lime." 


AMERICAN    CEMENTS.  71 

Prof.  S.  B.  Newberry  in  "  Mineral  Resources  of  the  United 
States,  1892,"  page  746,  says :  "Cement  possessing  hydraulic  pro- 
perties is  always  obtained  when  a  mixture  of  carbonate  of  lime  and 
clay,  in  proper  proportions,  is  strongly  heated.  Although  this  opera- 
tion appears  very  simple,  yet  the  chemical  reactions  which  take  place 
in  the  burning  and  hardening  of  cement,  and  the  chemical  nature  of 
the  cement  itself,  are  still  more  or  less  obscure.  Le  Chatelier  has 
shown,  perhaps  conclusively,  that  the  essential  constituent  of  Port- 
land cement,  burned  at  high  temperature,  is  a  compound  of  silica 
and  lime,  probably  of  the  formula  3CaO.SiO2.  The  alumina  and 
oxide  of  iron  of  the  clay  appear,  therefore,  to  play  an  unimport- 
ant part  in  the  hardening  of  cement.  Nevertheless,  Le  Chatelier 
failed  to  obtain  the  trisilicate  on  heating  lime  and  silica  together,  a 
mixture  of  lower  silicates  (bisilicate)  and  free  lime  being  always  ob- 
tained. It  is  evident,  therefore,  that  in-  order  to  produce  complete 
combination  of  the  silica  and  lime  at  the  temperature  of  the  cement 
kiln,  some  other  substance,  such  as  alumina  or  iron  oxide,  must  be 
present  to  act  as  a  flux.  By  fusion  with  the  oxyhydrogen  blowpipe, 
however,  the  writer  has  lately  succeeded  in  bringing  pure  silica  and 
lime  into  combination  in  the  proportion  required  by  Le  Chatelier's 
formula,  obtaining  a  product  which  showed  all  the  qualities  of  good 
cement.  It  appears,  therefore,  that  the  possibility  of  making  cement 
from  silica  and  lime  alone  is  only  a  question  of  temperature.  As  to 
the  part  played  by  the  alumina  and  iron  oxide  of  the  clay,  it  is  inter- 
esting to  recall  that  Dr.  Schott  long  ago  found  that  the  alumina  in 
cement  mixtures  can  be  completely  replaced  by  oxide  of  iron,  or  tjie 
oxide  of  iron  by  alumina,  without  injury  to  the  resulting  product.  He 
thus  obtained  cements  containing  only  silica,  lime,  and  alumina,  and 
equally  good  cements  containing  only  silica,  lime,  and  iron  oxide,  show- 
ing that  alumina  and  oxide  of  iron  act  in  a  precisely  similar  manner. 

"  The  exact  way  in  which  the  alumina  acts  in  promoting  the  com- 
bination of  silica  and  lime  is,  however,  still  more  or  less  uncertain. 
Le  Chatelier  considers  that  in  the  burning  of  cement  the  silica  and 
alumina  first  combine  with  a  small  amount  of  lime,  forming  a  fusible 
glass,  and  that  this  gradually  takes  up  more  lime,  becoming  more 
and  more  basic,  and  at  the  sane  time  less  fusible,  until  finally  the  all- 
important  trisilicate,  which  is  the  essential  constituent  of  cement,  is 
produced.  Le  Chatelier  has,  however,  shown  that  alumina  and  lime 


72  AMERICAN    CEMENTS. 

form  exceedingly  fusible  aluminates,  especially  when  the  lime  is 
present  in  large  proportion.  In  view  of  this  fact,  it  seems  to  the 
writer  much  more  probable  that  a  fusible  aluminate  is  first  produced, 
and  that  this  is  then  gradually  decomposed  by  the  silica  with  the 
formation  of  the  trisilicate,  the  alumina  finally  remaining  in  combina- 
tion with  a  comparatively  small  proportion  of  lime.  Substantially 
the  same  view  has  already  been  advanced  by  Michaelis.  Experi- 
ments now  in  progress  under  the  writer's  direction  are  expected  to 
throw  light  on  this  interesting  question 

"  It  is  well  known  that  in  making  Portland  cement  the  propor- 
tions of  basic  and  acid  constituents  (lime  and  clay)  must  be  almost 
absolutely  constant,  the  best  results  being  obtained  with  from  2.8  to 
3  parts  of  lime  to  i  part  of  silica.  In  natural  rock  cement,  if  the 
magnesia  be' disregarded,  the  clay  will  generally  be  found  to  be  very 
greatly  in  excess,  the  proportion  of  lime  to  silica  not  usually  ex- 
ceeding i)4  or  2  to  i.  At  the  low  temperature  at  which  the  natural 
rock  cement  must  of  necessity  be  burned,  it  is  probable  that  the  chief 
reaction  which  takes  place  is  the  combination  of  the  alumina  with 
the  lime,  and  that  most  of  the  silica  remains  uncombined.  The 
quick  setting  properties  of  hydraulic  cement  accord  closely  with  the 
behavior  of  calcium  aluminate,  and  indicate  that  the  latter  is 
the  active  constituent  in  cement  made  from  natural  rock.  The  pro- 
gressive hardening  of  this  cement  under  water  and  the  great  strength 
which  it  often  ultimately  attains  may  be  explained  by  the  gradual 
action  of  the  amorphous  silica  present  on  the  aluminate,  an  action 
similar  to  that  known  to  take  place  between  the  silica  of  pozzuolana, 
slag,  etc.,  and  slaked  lime." 

In  the  American  Cyclopaedia,  Vol.  IV.,  page  185,  the  following 
singular  theory  will  be  found  attributed  to  MM.  Rivet  and  Chatoney: 
"  Where  cements  are  calcined  at  a  high  heat,  silicate  of  alumina  and 
silicate  of  lime  are  formed,  which  on  the  addition  of  water  undergo 
decomposition  with  the  formation  of  aluminate  and  silicate  of  lime, 
containing  each  three  instead  of  six  equivalents  of  water,  which  is 
the  case  when  a  heat  only  sufficient  to  drive  off  the  carbonic  acid  of 
the  carbonate  of  lime  is  employed  ;  and  the  decomposition  which 
must  take  place  before  the  final  hydration  also  explains  the  slow 
setting." 

We  thus  have  here  a  variety  of  opinions  which  to  the  lay  mind 


AMERICAN    CEMENTS.  73 

must  give  rise  to  conjecture,  at  least,  and  to  those  who  take  a  deep 
interest  in  the  subject,  and  who  desire  to  arrive  at  the  truth,  must 
certainly  open  a  wide  field  for  research  and  experiment. 

With  a  view  to  the  acquirement  of  some  knowledge  of  a  practi- 
cal nature  in  regard  to  this  question  of  chemical  combinations,  the 
author  instituted  a  series  of  experiments,  which,  being  entirely  mechani- 
cal', except  as  to  the  analyses,  were  more  or  less  crude. 

One  of  these  consisted  in  pouring  three  quarts  of  rain  water, 
in  a  gallon  bottle  into  which  were  gradually  sifted  a  few  ounces  of 
natural  rock  cement  which  had  been  calcined  to  an  unverified  clinker 
and  ground  exceedingly  fine. 

The  bottle  was  shaken  vigorously  and  continuously  for  several 
minutes,  thus  giving  the  water  ample  time  to  act  on  the  powder 
before  the  latter  was  allowed  to  settle.  This  operation  was  repeated 
at  frequent  intervals  to  avoid  a  setting  of  the  cement,  as  would  have 
been  the  case  if  left  undisturbed.  The  following  day  the  water  was 
poured  off,  and  a  new  supply  used.  After  the  third  washing  the 
cement  was  dried  and  submitted  for  analysis. 

Previous  to  the  experiment  the  cement  had  been  carefully 
analyzed.  The  following  table  gives  the  analyses.  No.  i  before,  and 
No.  2  after,  washing. 

No.  i.  No.  2. 

Silica 24.30  26.01 

Alumina 6.62  7.07 

Oxide  of  Iron 2.41  2.16 

Lime 52.35  51-97 

Magnesia 6.16  6.52 

Potash  and  Soda 5.30  2.77 

Carbondioxide 2.10  2.26 

Loss .76  1.24 

Totals 100.00  100.00 

The  constituents  which  show  an  increase  in  percentages  are 
those  which  sustained  no  loss  in  the  washing,  while  those  which  show 
a  decrease  lost  a  portion  in  the  operation,  which  becomes  more 
noticeable  when  illustrated  by  ratios. 

No.  i.  No.  2. 

Ratio  of  silicic  acid  to  lime,  as    .     .     .     .     10  to  21.5          10  to  19.9 
?>       »       »        „     „  alkalies,  as     .     .     .     10  to  2.17         10  to  1.06 


74  AMERICAN    CEMENTS. 

The  ratios  as  between  silicic  acid  and  the  magnesia  and  alumina 
are  practically  constant. 

It  is  not  contended  that  this  experiment  is  at  all  conclusive,  but 
it  furnishes  evidence  that  magnesia  and  alumina  were  chemically 
combined  with  the  silica,  else  they  certainly  would  have  been  washed 
out,  or  at  least  partially  so. 

The  loss  of  7.45  per  cent,  in  the  lime  amounts  practically  to  the 
excess  above  its  true  combining  ratio  with  silicic  acid,  which  is  as 
10  to  1 8.6. 

The  prime  object  of  this  experiment  was  to  determine  the  truth 
or  falsity  of  the  theory  so  often  advanced,  that  the  magnesia  and 
alumina  are  inert  substances  in  a  cement,  and  the  results  demonstrate 
that,  by  a  careful  system  of  washing,  all  inert  or  uncombined  matter 
may  be  removed. 

The  fact  that  neither  magnesia  nor  alumina  are  separated  from 
the  silica  except  by  the  use  of  acids,  as  in  analysis,  should  be  a  suffi- 
cient refutation  of  the  idea  that  either  of  those  constituents  are  free 
and  inert  in  a  cement. 

The  difficulties  in  the  way  of  a  settled  theory  concerning  the 
fabrication  of  a  cement  are  furnished  by  the  almost  interminable  va- 
riations in  the  percentages  of  the  constituents,  silica,  alumina,  lime, 
and  magnesia. 

A  study  of  the  table  of  analyses  will  disclose  the  fact  that  no 
two  cements  are  alike  in  this  respect,  and  every  change  from  some 
fixed  standard,  with  the  varying  action  due  to  that  divergence  to  be 
accounted  for,  involves  the  subject  in  doubt,  and  opens  the  way  to 
endless  discussion  among  those  who  make  a  study  of  the  chemistry  of 
cements;  while  engineers,  architects,  and  others  who  are  in  a  posi- 
tion to  determine  the  brand  of  cement  to  be  used,  are  guided  by  prac- 
tical experience  in  the  use  of  the  various  brands,  paying  but  little 
regard  to  the  chemical  side  of  the  question. 

They  find  that  for  some  purposes  one  brand  of  cement  answers, 
while  for  another  class  of  work  some  other  brand  is  preferred.  It 
matters  little  to  them  whether  one  brand  contains  a  greater  or  less 
amount  of  magnesia  or  alumina  than  the  other.  They  desire  a 
satisfactory  result,  and,  as  a  rule,  are  far  less  prejudiced  than  any 
other  class  connected  with  the  art. 

A  cement  manufacturer  who  does  not  fully  and  unequivocally 


AMERICAN    CEMENTS.  75 

believe  his  own  production  to  be  in  every  conceivable  way  superior 
to  all  others  is  yet  to  be  found. 

It  is  a  fact  familiar  to  all  who  are  interested  in  the  subject  of 
hydraulic  cements,  that  the  question  of  quality  is  ordinarily  deter- 
mined by  tensile  strain  test.  It  is  a  convenient  method  of  reaching 
conclusions  as  to  the  relative  values  of  different  brands  of  cements. 

That  slight  attention  is  given  to  the  analysis  of  a  cement  is  due 
to  the  fact  that  a  mere  analysis,  as  it  appears  in  a  table,  does  not 
convey  to  the  average  mind  any  definite  meaning. 

And  when  several  analyses  are  compiled  in  one  table,  there  is  a 
confusion  of  ideas  as  to  the  significance  of  the  almost  endless  variety 
of  compositions  that  exist;  and  it  is  not  difficult,  therefore,  to 
account  for  the  almost  universal  use  of  the  tensile-strain  testing 
machines. 

It  should  be  understood  that  an  analysis  stands  mainly  as  a 
basis  for  further  calculations.  That  it  is  but  the  statement  of  a 
problem,  the  conclusions  of  which,  when  worked  out,  will  disclose 
the  percentages  of  silicates  or  active  setting  matter  in  the  cement, 
and,  consequently,  the  percentages  of  inert  substances ;  for  that  the 
constituents,  silica,  lime,  magnesia,  and  alumina  do  combine  chemi- 
cally in  fixed  proportions,  is  a  fact  established  beyond  all  controversy. 

If  all  cements  were  found  to  contain  these  constituents  in  true 
combining  proportions  there  would  be  but  little  left  to  be  said  on 
the  subject.  But  as  such  conditions  are  rarely,  if  ever,  met  with,  the 
most  that  can  be  done  toward  arriving  at  actual  values  is  to  deter- 
mine, from  a  given  analysis,  the  amount  of  silicates,  and  the  amount 
and  kind  of  inert  matter  present. 

When  a  system  for  so  doing  is  clearly  understood,  a  long  step 
will  have  been  taken  toward  a  clearer  and  better  understanding  of 
the  actual  merits  of  a  cement. 

It  will  then  be  discovered  how  utterly  unreliable  and  misleading 
are  the  readings  of  a  testing  machine,  unless  held  in  strict  subservi- 
ency to  a  superior  knowledge,  gained  only  by  a  thorough  study  of 
the  chemistry  of  cements. 

As  a  simple  method  for  calculating  the  percentages  of  silicates 
in  an  hydraulic  cement,  the  analysis  of  which  may  be  given,  we  have 
prepared  the  following  formulae,  which  will  be  found  to  serve  the  pur- 
pose. 


76 


AMERICAN    CEMENTS. 


Silica, 
Lime  , 


COMBINING    RATIO    OF    THE   VARIOUS    SILICATES. 
SILICATE    OF    LIME. 


A. 


K. 


1. 000 

1.864 


Lime  .... 
Silica. 


SILICATE    OF    MAGNESIA. 


(  . 


Silica i.ooo  Magnesia 

Magnesia I-33Q  Silica.     . 


i.ooo 
•536 


I.OOO 

.752 


SILICATE    OF    ALUMINA. 


Silica i.ooo 

Alumina 566 


Alumina 
Silica. 


:.ooo 
[.764 


BISILICATE    OF    LIME    AND    ALUMINA. 

G.                                                     H.  I. 

Silica     .     .     .  i.ooo      Lime      .     .     .  i.ooo      Alumina  .     .     i.ooo 

Lime      .     .     .   1.864      Alumina     .     .     .304      Silica     .  .     .     1.765 

Alumina     .     .     .566      Silica     .     .     .     .536      Lime      .  .     .     3.291 

BISILICATE    OF    LIME    AND    MAGNESIA. 


J. 

K. 

L. 

Silica 

.  i  .000 

Lime      .     . 

.     I.OOO 

Magnesia  . 

.       1  .000 

Lime      .     . 

.  1.864 

Magnesia   . 

•     .356 

Silica     .     . 

.     1.503 

Magnesia  . 

.     .665 

Silica 

•     .536 

Lime      ..    . 

.     2.803 

TRIS1LICATE    OF    LIME,    MAGNESIA,    AND    ALUMINA. 
M.  N.  O.  P. 

Silica    .     i.ooo  Lime     .     i.ooo  Magnesia  i.ooo  Alumina    i.ooo 

Lime     .     1.864  Magnesia    .356  Alumina      .852  Silica    .     1.765 

Magnesia    .665  Alumina      .304  Silica    .     1.503  Lime     .     3.291 

Alumina      .566  Silica    .       .536  Lime     .     2.803  Magnesia  1.172 

Although  the  formulae  which  are  headed  by  silica  are  all  that 
are  really  essential  for  a  correct  determination  of  the  percentages 
of  silicates,  yet  for  the  sake  of  simplifying  the  work,  and  rendering 


AMERICAN    CEMENTS.  77 

it  an  easy  task  to  calculate  the  percentages  of  silicates  or  active 
setting  matter,  and  thus  to  readily  determine  the  correct  amount  as 
well  as  the  kind  of  inert  substances  in  a  cement,  the  other  formulae 
have  been  given. 

To  determine  which  formula  to  use,  it  is  only  necessary  to  note 
which  of  the  component  parts  is  the  least  in  any  given  analysis,  then 
use  the  formula  which  is  headed  by  that  ingredient,  care  being  taken 
to  note  the  number  of  bases  under  consideration,  as  the  ratio  is  not 
the  same  for  all  classes  of  silicates. 

To  illustrate  the  use  to  which  these  formulae  may  be  put,  a  few 
of  such  numbers  in  the  table  of  analyses  as  will  best  serve  the  pur- 
pose of  employing  the  greatest  number  of  the  formulae  will  be  selected. 

ANALYZATION    OF    ANALYSES. 

No.  123  45 

Silica 24.33 —    6.58  =  17.75  —  17.75=00.00 

Alumina 3.73  -->•    3.73  =  'o.oo  —    o.oo  =    o.oo 

Lime 71.94—12.27=59.67  —  33.08  =  26.59 


Totals      ....     100.00        22.58  50.83        26.59 

Bisilicate  of  lime  and  alumina 22.58 

Silicate  of  lime 50.83 

Free  uncombined  lime      . 26.59 

Total 100.00 

Column  No.  I  gives  the  analysis  as  shown  in  No.  2  of  the  table 
of  analyses. 

Column  No.  2  shows  the  percentage  of  bisilicates  contained  in 
the  cement,  which  is  obtained  by  using  the  formula  |,  in  which  it  will 
be  seen  that  i.ooo  alumina  combines  with  1.764  silica. 

Therefore  alumina  3.73  X  1.764  =  6.58  silica,  and  by  the  same 
formula  it  will  be  seen  that  i  .000  alumina  in  a  bisilicate  is  cor 
with  lime  3.289,  therefore  3.73  X  3.289  =  12.27 

The  new  column  No.  2  is  now  formed  by  placing  the  three  con- 
stituents opposite  their  respective  names,  and  the  footing  shows  that 
the  total  percentage  of  bisilicate  of  lime  and  alumina  is  22.58,  which 
being  subtracted  from  column  No.  I  leaves  silica  1 7.75  and  lime  59.67, 
column  No.  3. 


78  AMERICAN    CEMENTS. 

Now  by  referring  to  formula  A,  it  will  be  found  that  i.ooo 
silica  combines  with  1.864  lime,  therefore  silica  17.75  X  1.864  =  33.08 
lime. 

This  gives  silicate  of  lime  50.83  as  found  in  column  No.  4. 
Column  No.  5  shows  the  amount  of  uncombined  material,  which  in 
this  case  is  26.59  free  lime. 

For  a  second  illustration  No.  5  of  the  table  of  analyses  will 
be  used. 

No.  123 

Silica 28.14         28.14         30.73 

Alumina 9.10  9.10  9.94 

Oxide  of  iron 3.20 

Lime 53-34         53-34         58.24 

Magnesia i.oo           i.oo           1.09 

Potash  and  soda 2.80 

Loss 2.42 

Totals 100.00         91-58       100.00 

The  first  column  contains  the  analysis  of  No.  5  in  full.  The 
second  column  contains  such  numbers  of  the  first  as  constitute  the 
essential  constituents  or  active  setting  matter  of  an  hydraulic  cement, 
and  is  reduced  to  hundreds,  as  shown  in  the  third  column,  by  divid- 
ing each  number  by  the  total  91 .58,  as,  for  instance,  silica  28.14  -f-  91 .58 
=  3°-73»  which  is  the  percentage  of  the  silica,  as  shown  in  the  third 
column,  along  with  the  percentages  of  alumina,  lime,  and  magnesia, 
which  in  the  following  table  will  be  found  under  No.  i . 

No.  1234567 

Silica  .  30.73  —  1.64  =  29.09 — 15.90=13.19 — 13.19=  o.oo 
Lime  .  58.24  —  3.05  =  55.19  —  29.65  =  25.54  —  24.58=  0.96 
Magnesia  1.09 — 1.09=  o.oo —  0.00=  o.oo —  0.00=  o.oo 
Alumina  9.94—-  .93  =  9.01  —  -  9.01  =  o.oo —  0.00=  o.oo 
Totals  100.00  IT;  i  54.56  37.77  0.96 

Trisilicate  of  lime,  magnesia,  and  alumina    ....       6.71 

Bisilicate  of  lime  and  alumina 54-56 

Silicate  of  lime 37-77 

—  99-04 

Uncombined  base  (lime) 0.96 

Totals  .  100.00 


AMERICAN    CEMENTS.  79 

There  being  three  bases  in  this  cement,  it  is  evident  that  the 
first  formula  to  be  used  will  be  found  under  the  head  of  trisilicatesr 
and  the  magnesia  being  the  lesser  in  quantity,  formula  O  is  used  as 
follows :  — 

Magnesia  1.09  X  1.503  =  1.64  silica,  which  is  placed  in  column 
2  opposite  silica. 

Again,  magnesia  1.09  X  2.803  =  3-°5  lime,  which  is  placed  in 
column  2  opposite  lime. 

And  lastly,  magnesia  1.09  X  .852  =  .93  alumina,  which  being 
placed  in  column  2  opposite  alumina,  and  the  total  magnesia  also 
being  placed  in  column  2,  completes  the  column,  the  footing  of 
which  shows  that  the  total  amount  of  trisilicate  in  the  cement  is  6.71. 

By  subtracting  column  2  from  column  i,the  remainder  is  shown 
in  column  3,  and  as  there  are  now  but  two  bases,  lime  and  alumina, 
in  this  column,  it  is  clear  that  the  proper  formula  will  be  found 
under  the  head  of  bisilicate  of  lime  and  alumina,  and  as  the  alumina 
is  the  lesser  in  quantity,  formula  I  is  used  in  the  same  manner  as  in 
the  previous  analyzation,  which  in  this  analysis  forms  column  4, 
showing  54.56  bisilicate  of  lime  and  alumina.  The  remainder,  in 
column  5,  shows  but  one  base,  and  as  it  is  slightly  in  excess  of  the 
remaining  silica,  formula  A  is  used,  the  same  as  in  the  previous 
table,  resulting  in  column  6,  which  shows  37.77  silicate  of  lime. 

Column  7  exhibits  the  total  remaining  uncombined  matter  in 
the  cement,  which  is  found  to  be  less  than  one  per  cent. 

Number  15  of  the  table  of  analyses  is  selected  for  the  next  illus- 
tration. 

As  in  the  preceding  table  the  inert  matter  is  deducted,  and  the 
active  ingredients  are  calculated  to  hundred  parts,  and  placed  in 
column  No.  i. 

No.  123  4567 

Silica.     .  22.61  — 4.72  =  17.89  —  16.63=    *-26 — 1.26=    o.oo 

Lime.     .  62.15 — 8-8°  =  53-35 — 31.00  =  22.35  —  2.35  =  20.00 

Magnesia  3.14  —  3.14  =    o.oo  —    o.oo  =    o.oo  —  o.oo  =    o.oo 

Alumina.  12.10  —  2.68=    9.42 —    9.42=    o.oo  —  0.00=^    o.oo 


Totals.  100.00      19.34  57.05  3-6i        20.00 


80  AMERICAN    CEMENTS. 

Trisilicate  of  lime,  magnesia,  and  alumina       ....     19.34 

Bisilicate  of  lime  and  alumina 57-O5 

Silicate  of  lime 3.61 

Percentage  of  silicates 80.00 

„  „  uncombined  base 20.00 

Total 100.00 

The  following  is  an  analyzation  of  analysis  No.  20  of  the  table 
of  analyses. 

The  non-essentials  being  discarded,  the  analysis  in  hundred  parts 
appears  in  column  No.  i . 

No.  1234567 

Silica      ....  28.96 — 15.87=13.09 — 00.54=12.55 — 11.03=1.52 

Lime       ....  51.16 — 29.58=21.58 — 01.00=20.58 — 20.58=0.00 

Magnesia    .     .     .  10.89 — 10.53=00.36 —  0.36=  o.oo —  0.00=0.00 

Alumina      .     .     .  8.99 —  8.99=  o.oo —  0.00=  o.oo —  0.00=0.00 


Totals       .     .  100.00     64.97  1.90  31.61    1.52 

Trisilicate  of  lime,  magnesia,  and  alumina      ....     64.97 

Bisilicate  of  lime  and  alumina        1.90 

Silicate  of  lime 31.61 

Percentage  of  silicates 98.48 

„  „    uncombined  matter 1.52 

Total 100.00 

The  analysis  of  a  raw  cement  stone  being  given,  and  it  being 
desired  to  reduce  it  to  the  percentages  of  silicates,  which  would 
appear  after  calcination,  the  following  will  be  found  an  easy  method 
for  making  the  calculation. 

Analysis  No.  40  in  the  table  is  that  of  a  raw  cement  stone,  as 
will  be  seen  in  the  reference  table.  The  carbon  dioxide  was  sub- 
tracted from  the  calcium  carbonate  for  the  sake  of  convenience  in 
placing  it  in  the  table.  The  analysis  of  the  stone  is  given  in  column 
No.  i  in  the  following  table. 

No.  123 

Silica 17.50  17.50  28.92 

Carbonate  of  lime      .     .     .     65.20  (lime)  36.^1  60.34 


AMERICAN    CEMENTS. 


81 


Alumina 6.50  6.50  10.74 

Oxide  of  iron 3.00 

Water  and  loss 7.80 

Totals 100.00  60.51  100.00 

Column  2  contains  the  essential  constituents,  the  carbonate  of 
lime  being  reduced  to  lime.  By  reference  to  the  table  of  chemical 
combinations,  it  will  be  seen  that  carbonate  of  lime  is  composed  of 
lime,  56,  carbon  dioxide,  44  ;  therefore  65.20  X  56  =  36.51  lime. 

The  essential  constituents,  as  shown  in  column  2,  are  reduced  to 
hundreds  in  column  3,  and  is  shown  in  column  i  of  the  following 
table. 


No. 

Silica  . 
Lime  . 
Alumina 

Totals 


I  2 

28.92    18.95 

60.34   —  35.34 

10.74—  io-74 


3  4 

9.97—    9-97 

25.00  —  18.58 

o.oo  —    o.oo 


s 

0.00 

6.42 

0.00 


100.00 


65.03 


Bisilicate  of  lime  and  alumina  . 
Silicate  of  lime  . 


28.55        6.42 

.     .     65.03 

.     .     28.55 


Percentage  of  silicates 

„  uncombined 


Total 


93.58 
6.42 

IOO.OO 


Should  carbonate  of  magnesia  appear  in  the  analysis  of  a  cement 
stone,  the  amount  of  magnesia  will  be  found  by  multiplying  the  car- 
bonate by  .476,  as  shown  in  the  table  of  chemical  combinations,  and 
the  product  is  placed  in  the  column  of  constituent  parts,  as  was  done 
with  the  lime  in  the  preceding  table. 

The  following  analyzations  are  taken  from  the  corresponding 
numbers  in  the  table  of  analyses,  and  reduced  to  hundred  parts,  the 
analysis  appearing  in  column  No.  I. 


No.  47- 

No.  12 

Silica 21.48  —  13.71 

Lime 70.75  —  25.57 


'  3  4  5 

7-77  —    7-77  =    0.00 
45.18  —  14.48  =  30.70 


82  AMERICAN    CEMENTS. 

Alumina 7.77  —    7.77  =    o.oo  —    o.oo  =    o.oo 


Totals 100.00       47.05  22.25        30.70 

Bisilicate  of  lime  and  alumina 47.05 

Silicate  of  lime 22.25 

Total  silicates "   69.30 

Free  lime 30.70 

Total 100.00 

No.  48. 

No.  12  34  5  67 

Silica  .  22.35  —  1.76  =  20.59  —  9-99  =  10.60  —  10.60  =  o.oo 
Lime  .  69.82  —  3.28  =  66.54  —  18.63  =  47-91  —  19*76  «=  28.15 
Magnesia  1.17  —  1.17  =  o.oo  —  o.oo  =  o.oo  —  o.oo  =  o.oo 
Alumina  6.66  —  i.oo  =  5.66  —  5.66  =  o.oo  —  o.oo  =  o.oo 


Totals  100.00       7.21  34.28  30.36       28.15 

Silicate  of  lime,  magnesia,  and  alumina 7.21 

Silicate  of  lime  and  alumina 34.28 

Silicate  of  lime 30.36 

Percentage  of  silicates • 7!.85 

„  „  free  base 28.15 

Total 100.00 

No.  50. 

No.  12345 

Silica 22.56 — 14.15=    8.41  —    8.41=    o.oo 

Lime 69.42  —  26.39  =  43.03  —  15.68=27.37 

Alumina   .  8.02  —    8.02  =    o.oo  —    o.oo  =    o.oo 


Totals 100.00        48.56  24.09        27.37 

Silicate  of  lime  and  alumina 48.56 

Silicate  of  lime 24.09 

Percentage  of  silicates 72.65 

Free  lime 27.35 

Total  100.00 


AMERICAN    CEMENTS.  83 

No.  52. 

No.  1234567 

Silica  .  23.70  —  3.58  =  20.12  —  11.05=  9.07 —  9.07=  o.oo 
Lime  .  65.63  —  6.67  =  58.96  —  20.60  =  38.36  —  16.91  =  21.45 
Magnesia  2.38  — •  2.38  =  o.oo  —  o.oo  =  o.oo  —  o.oo  =  o.oo 
Alumina  8.29  —  2.03  =  6.26  —  6.26  =  o.oo  —  o.oo  =  o.oo 


Totals      100.00       14.66  37.91  25.98        21.45 

Silicate  of  lime,  magnesia,  and  alumina 14.66 

Silicate  of  lime  and  alumina 37-91 

Silicate  of  lime 25.98 


Percentage  of  silicates 
Percentage  free  base  . 


Total 100.00 

The  foregoing  calculations  sufficiently  illustrate  the  system  of 
calculating  the  percentages  of  silicates  or  active  setting  matter  in  a 
cement,  or  cement  rock,  from  such  analyses  as  are  usually  rendered 
by  chemists  and  analysts.  They  also  determine  the  classes  of  sili- 
cates which  may  be  present  and  their  percentages. 

In  a  cement  containing  the  three  bases,  lime,  magnesia,  and 
alumina,  there  may  be  found  the  three  classes,  namely,  triple,  double, 
and  single  silicates. 

As  has  already  been  stated,  a  cement  containing  two  or  three 
silicates  is  superior  in  quality  to  that  which  contains  but  one. 

To  illustrate,  let  us  suppose  a  cement  to  contain  silica,  lime,  and 
alumina  in  exact  combining  proportions  and  forming  a  double  sili- 
cate of  lime  and  alumina,  as  in  the  following :  — 

Silica 29.14 

Lime       54-34 

Alumina 16.52 


Total .     .     .  100.00 

Now  if  we  take  8.00  from  the  alumina,  and  add  an  equal  amount 
to  the  silica  and  lime  in  the  proportions  of  2.80  to  the  silica  and  5.20 
to  the  lime  =  8.00,  the  new  table  will  be  formed  as  shown  in  column 


84  AMERICAN    CEMENTS. 

No.  I  below,  and  the  double  and  single  silicates  will  appear  in  the 
second  and  third  columns  respectively. 

No.  i  2  3 

Silica 31.94 — 15.04  =  16.90 

Lime 59-54  —  28.04=31.50 

Alumina 8.52  —    8.52  =    o.oo 


Totals 100.00        51.60       48.40 

Bisilicate  of  lime  and  alumina  .     .  51.60 

Silicate  of  lime .  48.40 


Total 100.00 

There  can  be  no  question  whatever  that  a  cement  formed  with 
the  two  classes  of  silicates,  as  shown  in  the  latter  table,  will  be  supe- 
rior in  quality  to  that  shown  in  the  preceding  table,  which  is  due  to 
the  fact  that  in  a  cement,  whether  natural  or  artificial,  lime  is  superior 
to  alumina  as  a  base,  in  the  mortar  of  masonry  or  concrete,  used 
either  above  or  below  water,  and  especially  is  this  true  in  regard  to 
masonry  or  concrete  submerged  in  sea  water. 

No  better  demonstration  of  this  fact  is  afforded  than  in  the  use 
of  Tiel  hydraulic  lime,  which  contains  less  than  2  per  cent,  of  alu- 
mina. Although  this  material  contains  a  large  percentage  of  uncom- 
bined  lime,  it  has  never  been  surpassed  in  its  ability  to  resist  the 
action  of  sea  water,  and  those  cements  which  have  failed  in  sea 
water,  whether  natural  or  artificial,  are  found  to  contain  a  large  pro- 
portion of  alumina.  Therefore,  as  shown  in  the  last  two  tables,  the 
alumina  may  vary  50  per  cent,  in  amount,  and  still  remain  within  the 
limits  of  true  combining  proportions,  yet  it  is  extremely  probable,  and, 
indeed,  it  may  be  stated  as  an  absolute  certainty,  that  as  between 
the  two  compositions  referred  to,  the  latter  would,  while  the  former 
would  not,  sustain  continued  immersion  in  sea  water. 

It  seems  desirable  that  some  explanation  be  made  or  reason 
given  for  the  position  taken  in  regard  to  the  combining  ratio  of  the 
various  silicates.  To  make  a  concise  statement  of  the  conflicting 
opinions  concerning  this  vexed  question,  it  is  best  to  give  them  in 
the  order  of  their  popularity. 

First.     Hydraulic  cement  is  produced  by  the  formation  of  sili- 


AMERICAN    CEMENTS.  85 

cate  and  aluminate  of  lime  during  calcination.  Magnesia,  if  present; 
is  inert  or  uncombined. 

Second.  By  the  formation  of  bisilicate  of  lime  and  alumina 
during  calcination,  magnesia,  if  present,  forms  silicate  and  aluminate 
of  magnesia. 

Third.  The  formation  of  silicate  of  lime  during  calcination,  the 
alumina  and  magnesia  remaining  uncombined,  or  playing  an  unim- 
portant part. 

Fourth.  That  after  calcination  the  constituents,  silica,  and 
whatever  bases  may  be  present,  exist  in  a  free  state,  and  that  by  the 
application  of  water,  a  silicate  is  formed  combining  all  the  bases 
present  in  certain  proportions ;  the  excess,  if  any,  is  uncombined. 

Fifth.  Whether  the  material  is  natural  cement  rock  or  is  arti- 
ficially compounded,  the  formation,  during  calcination  of  triple,  double, 
and  single  silicates  occurs  (dependent  on  the  number  of  bases  pres- 
ent), in  certain  fixed  proportions,  any  excess,  whether  of  silica  or 
the  bases,  remaining  uncombined. 

The  preceding  chapters,  the  table  of  chemical  combinations,  and 
that  of  combining  ratios,  are  sufficient  evidence  of  our  belief  in  the 
correctness  of  the  fifth  proposition,  and  it  is  but  just  and  proper  to 
state  that  we  are  substantially  alone  in  this  belief. 

The  nearest  approach  to  it  is  the  opinion  of  Professor  Cox,  who> 
however,  as  shown  by  his  writings,  inclines  to  the  fourth  proposition. 

Without  wishing  to  arrogate  any  special  knowledge  of  the  art, 
or  to  attempt  the  building  up  of  a  new  theory  in  relation  to  the  chem- 
ical combinations  existing  in  a  cement,  or  contradictorily  oppose  the 
views  of  others  on  this  subject,  yet  it  is  due  to  state  that  we  find  it 
impossible  to  accept  many  of  the  opinions  given,  such,  for  example, 
as  that  both  silicate  of  lime  and  aluminate  of  lime  are  formed  in  a 
cement. 

While  it  is  true  that  aluminate  of  lime  can  be,  and  is,  formed  by 
the  action  of  heat  when  these  constituents  are  treated  separately, 
that  it  can  so  form  when  in  the  presence  of  silica  and  lime,  we  do 
not  believe. 

We  have  already  shown  that  alumina  has  both  a  basic  and 
acidic  character,  although  both  are  comparatively  weak;  and  we 
believe  that  its  acidic  character  entirely  disappears  when  in  the 
presence  of  the  much  more  powerful  silicic  acid,  and  that  when  in 


86  AMERICAN    CEMENTS. 

the  presence  of  that  acid  it  can  only  assume  the  properties  due  to 
its  basic  character,  and  it  therefore  combines  with  silica  in  certain 
fixed  proportions  with  lime  and  magnesia;  and  therefore  when  these 
three  bases  are  present,  with  silicic  acid,  a  combination  is  formed  by 
the  acid  and  the  three  bases  in  fixed  and  unalterable  proportions,  in 
accordance  with  the  law  of  atomic  weights. 

There  can  be  no  doubt  that  if  a  mixture  should  be  compounded 
which  contained  a  small  amount  of  silica  and  a  large  amount  of 
lime  and  alumina,  the  excess  of  the  two  bases  over  and  above  their 
equivalents  of  silica  would  combine,  forming  aluminate  of  lime. 

But  inasmuch  as  there  are  no  known  cements,  whether  natural 
or  artificial,  which  contain  alumina  in  excess  of  its  combining  ratio 
with  the  silica  and  lime  present,  it  is  needless  to  pursue  this  subject 
further. 

That  magnesia  can  remain  uncombined,  when  present  with 
silicic  acid  and  lime,  or  lime  and  alumina,  is  a  theory  which  has  been 
so  often  disproved,  that  it  seems  incredible  that  advocates  of  this 
fallacy  should  be  found  among  the  higher  authorities,  who  claim 
that  in  an  artificial  cement  more  than  three  per  cent,  is  not  to  be 
tolerated,  while  in  natural  rock  cements  it  is  uncombined,  and  there- 
fore inert. 

The  Rosendale  cements,  which,  in  quality  and  general  excel- 
lence, stand  in  the  front  rank  among  American  rock  cements,  con- 
tain from  15  to  1 8  per  cent,  of  magnesia.  These  cements  are  never 
hydrated,  being  packed  at  the  mill-spout  as  fast  as  ground;  and 
when  used,  are  taken  from  the  packages  and  mixed  with  sand  and 
water,  and  immediately  applied  in  masonry  or  concrete. 

If  the  magnesia  in  these  cements  is  in  a  free  and  uncombined 
state,  as  claimed  by  many  writers,  it  must  certainly  follow  that  in  the 
subsequent  hydration,  expansion  and  disruption  of  the  masonry  is 
inevitable.  And  so,  if  these  cements  are  kept  in  packages  any  length 
of  time,  say  three  or  four  months,  as  often  occurs  in  the  hands  of 
dealers  in  cements,  the  hydration  of  the  free  magnesia  would  cer- 
tainly expand  the  packages  and  burst  the  hoops.  And  yet  this  dis- 
tension of  packages  never  occurs,  and  the  idea  of  a  disruption  of 
masonry  through  the  use  of  Rosendale  cement  is  simply  absurd. 
Millions  of  barrels  of  this  brand  of  cement  are  used  in  many  of  the 
greatest  engineering  and  architectural  works  in  the  country,  such  as 


AMERICAN    CEMENTS.  87 

the  high  bridge  over  the  Harlem,  the  New  York  and  Brooklyn  sus- 
pension bridge,  the  Croton  aqueducts,  the  tallest  buildings  in  lower 
Broadway,  —  in  short,  it  may  be  said  that  New  York  and  Boston  are 
built  with  this  cement,  —  and  furthermore,  the  Akron,  Milwaukee, 
Utica,  and  Mankato  brands  of  cement,  all  contain  practically  as 
much  magnesia  as  do  the  Rosendale  brands ;  and  yet  there  is  no 
known  instance  of  any  of  these  brands  ever  expanding  in  masonry, 
and  magnesian  cements  are  used  in  this  country  to  the  extent  of 
nearly  five  million  barrels  yearly.  These  facts  alone  stand  as  a 
complete  refutation  of  the  absurd  theory  that  magnesia  is  free  in 
these  cements. 

It  is  as  quick  to  combine  with  silica  as  is  lime.  During  calcina- 
tion it  parts  with  its  carbon  dioxide  at  a  lower  heat  than  is  required 
for  the  expulsion  of  that  acid  from  the  lime,  and  becoming  caustic  in 
advance  of  the  lime,  is  the  first  to  attack  the  silica,  freeing  the  latter 
from  its  combination  with  alumina,  thus  rendering  the  silica  as  free 
silicic  acid,  and  if  the  high  heat  is  continued,  a  reaction  takes  place, 
and  chemical  combination  ensues  between  the  acid  and  the  three 
bases,  in  accordance  with  their  atomic  weights,  as  fully  illustrated 
in  the  table  of  combining  ratios. 

A  simple  illustration  of  the  fact  that  the  reaction  follows  the 
separation  of  the  alumina  from  the  silica,  and  a  chemical  combina- 
tion with  the  acid  and  all  the  bases  takes  place,  is  afforded  by  the 
following  experiment :  — 

First.  Take  a  piece  of  magnesian  cement  rock  and  from  it 
secure  two  pieces  weighing  one  or  two  pounds  each,  and  after  they 
have  been  gradually  dried  out,  to  prevent  what  is  known  by  kiln  men 
as  "popping,"  which  is  caused  by  a  bursting  into  small  pieces  through 
the  sudden  conversion  of  the  moisture  contained  in  the  rock  into 
steam,  place  both  these  pieces  in  a  smith's  forge  and  rapidly  drive 
them  up  to  nearly  a  white  heat,  then  suddenly  withdraw  one  of  the 
pieces  from  the  forge,  and  as  quickly  as  possible  crush  it  to  powder 
while  hot. 

Second.  Continue  the  heat  with  the  other  piece  for  half  an 
hour  or  so,  then  stop  the  blower  and  allow  the  piece  to  cool  gradu- 
ally, keeping  it  covered  in  the  forge  until  it  is  cold,  then  crush  to 
powder. 

Third.     Keep  the  two  samples  separate  and  wet  them  into  balls, 


88 


AMERICAN    CEMENTS. 


patties,  or  briquettes,  and  note  the  difference  in  the  action  of  the 
two.  The  first  will  heat,  expand,  and  check,  and  if  placed  under 
water  will  become  of  a  mud-like  consistency,  and  if  in  air,  it  will 
crumble  into  dust-like  ashes  ;  while  the  second  sample  will  not  heat, 
will  not  expand  or  check,  and  after  an  hour  in  air  will  sustain  sub- 
mersion and  become  hard. 

The  first  sample  was  withdrawn  from  the  heat  after  the  expulsion 
of  the  carbon  dioxide,  and  before  it  had  time  for  the  reaction  and 
formation  of  silicates,  and  the  constituents  were  in  a  free  condition, 
as  shown  by  the  heat  and  expansion  when  hydrated,  while  the  second 
sample  was  accorded  the  necessary  time  for  such  reaction  and  chemi- 
cal combination ;  thus  proving  the  truth  of  our  assertion,  that  when- 
ever present  with  silica  and  lime,  and  under  high  and  continued  heat, 
both  magnesia  and  alumina  combine  with  the  silicic  acid  in  precisely 
the  same  manner  as  lime  combines,  in  certain  fixed  proportions, 
according  to  the  law  of  atomic  weights. 

A  table  of  the  atomic  weights  of  such  elements  as  are  found  in 
hydraulic  cements  is  herewith  given.  The  numbers  indicate  the 
relative  weights  of  the  atoms  constituting  the  elements. 


1 
ELEMENTS. 

SYMBOL. 

ATOMIC  WEIGHT. 

Aluminum  

AL 

27. 

Calcium               .               . 

Ca. 

70.0 

C. 

I  I.Q7 

Hydrogen  .               

H. 

I. 

Fe. 

CC.Q 

Magnesium                    .     .     .     . 

Mg. 

27.0 

Mn. 

54.8 

Oxygen                           .     . 

O. 

i  ;.q6 

Kalium  (Potassium)     . 
Sulphur      

K. 
S. 

39-03 
31.98 

Si. 

28. 

Sodium  (Natrium)       . 

Na. 

22.QQ 

Although  the  system  employed  in  calculating  the  percentages  of 
the  various  chemical  combinations  which  occur  in  hydraulic  cements 
is  familiar  to  many,  yet  a  desire  has  been  expressed  that  it  be  illus- 
trated in  a  plain  and  practical  manner,  which  may  be  readily  under- 


AMERICAN    CEMENTS.  89 

stood  by  those  who  have  little  time  to  devote  to  such  study,  and  for 
this  reason  a  place  is  given  to  the  following  calculations. 

SILICATE  OF  LIME. 

Silica  (SiO2)  is  a  chemical  combination  of  silicon  and  oxygen  in 
the  proportion  of  one  atom  of  silicon  (Si)  to  two  atoms  of  oxygen  (O). 

By  reference  to  the  table,  it  will  be  seen  that  the  atomic  weight 
of  silicon  is  28.,  and  that  of  oxygen  is  15.96.  Two  atoms  of  oxygen 
will  therefore  weigh  31.92. 

Thus,  28.  +  31.92  =  59.92  =  silica.  By  dividing  each  number 
by  59.92  we  get  the  percentage  of  each. 

28.00  4-  59-92  =  Silicon  46.73  >       1QQ  Silica  (Sio  }> 
31.92  -f-  59.92  =  Oxygen  53.27  ) 

Employing  the  same  method  with  reference  to  lime  (CaO)  we 
find  that  the  atomic  weight  of  calcium  is  39.90,  which,  being  added 
to  one  oxygen  15.96  =  55.86  =  lime. 

Therefore    39-9°  *  55-86  -  Calcium  7M3  >       loo   !ime  (CaO). 
15.96--  55-86  =  Oxygen  28.57  ) 

Silicate  of  lime  is  formed  by  a  combination  of  silica  and  lime  in 
the  proportion  of  one  part  of  the  former  to  two  parts  of  the  latter, 
the  combining  numbers  of  which  are  as  already  given. 


Silica  =  59-92  1=171.64. 

Lime  (55-86  X  2)  111.72  J 


2  Lime  (55.86  X  2)  111.72 

59.92  -f-  171.64  =  Silica  34.91)  =100     Silicate     of    Lime   (2CaO, 

111.72  -r-  171.64  =  Lime  65.09  )  SiO2). 

CARBONIC    ACID. 
Carbon  (C)  11.97      7  =       8 
2  Oxygen  (0)31.92) 

Carbon  1 1.07  -=-43.80  =  Carbon  27.27  "> 

'    '  \  =  100  Carbonic  Acid  (CO2). 
Oxygen  3 1 .92  -=-  43.89  =  Oxygen  72.73  > 


CARBONATE  OF  LIME. 
Lime  55.86 
Carbonic   Acid  43.89 
55.86 -=-99.75  =  Lime  56  )  =    100     Carbonate    of    Lime 

43-89  -T-  99.75  =  Carbonic  Acid  44  >  (CaO,  CO2). 


|=  99-75- 


90  AMERICAN   CEMENTS. 

SILICATE  OF  MAGNESIA. 

Magnesium  23.9    7        39>86  Magnesia  (MgO). 
Oxygen         15. 96) 

1  Silica  59.96  I  = 

2  Magnesia  (39.86  X  2)    79.72  ) 

59.96  -f-  139.68  =  Silica  42.92  }  =  Silicate  of  Magnesia  (2MgO. 
79.72  -T-  139.68  =  Magnesia  57.08  >  SiO2). 

Among  the  manufacturers  of  artificial  cements  during  the  past 
twenty  years  or  so  there  has  been  a  constantly  growing  ambition  to  in- 
crease the  number  of  pounds  of  tensile  strain  their  cement  will  sustain, 
expecting  thereby  to  improve  the  quality  of  their  respective  brands. 

Goaded  on  by  the  universal  preference  for  the  brands  showing 
the  highest  tests,  they  are  striving  by  every  means  at  their  command 
to  attain  still  higher  results. 

Many  experiments  were  tried  by  adding  foreign  substances  in 
varying  percentages,  among  which  may  be  mentioned  sulphate  of 
lime,  which  still  obtains  among  nearly  all  the  producers  of  Portland 
cement. 

It  is  not  denied  by  the  manufacturers  that  by  its  use  much 
higher  short  time  tests  are  possible,  and  they  justify  its  use  by  their 
assurance  to  the  public  that  they  do  not  use  too  much  of  it,  thereby 
admitting  its  harmful  character,  which  is  so  great  that  the  German 
society  of  Portland  cement  manufacturers  publicly  advertise  that  the 
members  of  that  society  are  not  permitted  to  use  more  than  three 
per  cent,  of  this  material  in  their  cements. 

No  one  will  claim  that  a  mixture  of  sulphate  of  lime  in  a  cement 
is  beneficial ;  on  the  contrary,  it  is  well  known  to  be  harmful,  and 
that  a  cement  is  better  without  it,  even  though  it  may  not  test  so 
high  by  a  few  pounds  in  one-day  or  seven-day  tests. 

Its  use  simply  illustrates  the  unreasoning  desire  to  reach  a  little 
higher  mark  in  testing. 

Several  years  ago  it  was  discovered  that  an  addition  of  lime 
beyond  its  equivalent  of  silica  would  permit  of  a  higher  heat  in  cal- 
cination, which  in  turn  gave  a  cement  the  quality  of  sustaining  higher 
short  time  tests ;  and  the  manufacturers  were  not  slow  in  availing 
themselves  of  this  apparent  advantage. 

And  thus  the  proportion  of  lime  has  been  gradually  increased 


AMERICAN    CEMENTS.  91 

until  to-day  there  will  be  found  in  all  brands  of  Portland  cement,  as 
has  already  been  stated,  from  2.7  to  to  3.2  parts  of  lime  to  I  part  of 
silica. 

Although  it  was  learned  that  by  increasing  the  proportion  of 
lime  higher  short  time  testing  results  followed,  yet  it  became  evident 
that  such  a  cement  must  necessarily  contain  a  large  proportion  of 
free  lime,  which  was  not  considered  a  desirable  result ;  and  to  over- 
come this  unpleasant  difficulty,  some  of  the  leading  authorities 
asserted  that  the  excess  of  lime  was  taken  up  and  combined  with  the 
alumina,  forming  aluminate  of  lime,  as  shown  in  the  tables  quoted 
from  Professor  De  Smedt,  who,  it  will  be  observed,  gives  the  combin- 
ing proportions  as  silica  34.88  and  lime  65.12,  the  ratio  being  silica 
i,  lime  1.86,  and  the  ratio  of  alumina  I  and  lime  2,  to  form  aluminate 
of  lime. 

But  as  the  percentage  of  lime  has  been  gradually  increased,  it 
has  been  found  necessary  to  establish  a  new  ratio  as  between  the 
silica  and  lime,  the  German  authorities  taking  the  lead  in  this  new 
departure ;  and  it  is  now  gravely  asserted  that  I  molecule  of  silica 
combines  with  3  molecules  of  lime,  making  the  ratio  I  of  the  former 
to  2.79  of  the  latter. 

As  the  modern  Portland  contains  from  2.80  to  3.25  of  lime  to  I 
of  silica,  the  lime,  which  is  in  excess  of  the  new  ratio,  is  conveniently 
taken  up  by  the  alumina,  forming  aluminate  of  lime. 

Thus  for  the  present,  at  least,  the  authorities  on  Portland 
cement  seem  to  have  the  ratio  satisfactorily  adjusted. 

It  is  probable,  however,  that  some  way  would  be  found  to  show 
conclusively  that  i  part  of  silica  combined  with  4  or  more  parts  of 
lime,  should  some  genius  discover  a  way  to  produce  higher  testing 
results  by  such  a  manipulation  of  proportions. 

To  show  the  tendency  toward  increasing  the  proportion  of  lime, 
which  is  done  solely  for  the  purpose  of  gaining  higher  short  time 
tests,  it  is  only  necessary  to  take  as  an  illustration  the  analysis  of 
one  of  the  foremost  brands  of  English  Portland  cements  ;  a  cement 
which,  twenty  years  or  so  ago,  commanded  the  largest  sale,  and  the 
highest  price  of  any  cement  in  the  American  markets. 

The  analysis  was  carefully  conducted  by  the  painstaking  and 
conscientious  chemist,  Prof.  E.  T.  Cox,  while  he  was  State  geologist 
of  Indiana. 


92  AMERICAN    CEMENTS. 

The  constituent  parts  of  this  cement,  after  discarding  the  non- 
essentials,  will  be  found  in  column  No.  I  of  the  following  table,  and 
the  percentage  of  silicates  appears  in  the  succeeding  columns. 

No.  1234567 

Silica  .  30.89  —  1.65  =  29.24  —  1744  =  ii. 80  —  11.57  =  00.23 
Alumina  10.82  —  0.94  =  9.88  —  9.88  =  o.oo  —  o.oo  =  o.oo 
Lime  .  57.19  —  3.08=54.11  — 32.52=21.59  —  21.59=00.00 
Magnesia  i.io — 1.10=  o.oo —  0.00=  o.oo —  0.00=  o.oo 


Totals  100.00       6.77                       59.84  33.1 6        00.23 

Silicate  of  lime,  magnesia,  and  alumina 6.77 

Silicate  of  lime  and  alumina 59.84 

Silicate  of  lime 33-i6 

Total  silicates 99-77 

Uncombined  silica 00.23 


Total 100.00 

It  will  be  observed  that,  in  the  matter  of  proportions,  this  cement 
was  as  nearly  perfect  as  it  was  possible  to  be  made.  It  was 
tested  frequently  by  the  author  for  many  years,  and  it  was  never  known 
to  check  or  expand,  and  it  became  exceedingly  hard  and  permanent  in 
masonry,  and  was  used  in  sidewalks  and  similar  work,  almost  to  the 
exclusion  of  all  other  brands,  and  yet  it  would  rarely  exceed  250  Ibs. 
in  a  seven  days'  test.  Neither  did  it  become  glassy  and  brittle  with 
age,  like  the  modern  Portland  cements,  a  result  due  entirely  to  the 
demand  for  higher  short  time  tests ;  a  demand  which,  to  the  detri- 
ment of  its  quality,  has  compelled  the  manufacturers  of  the  brand  in 
question  to  increase  the  proportion  of  lime,  as  may  be  seen  by  refer- 
ence to  No.  10  of  the  table  of  analyses,  in  which  it  will  be  observed 
that  the  ratio  of  silica  to  lime  is  as  I  to  3.07,  while  the  ratio  in  the 
earlier  analysis  as  herein  given  is  I  to  1.85+,  which  is  practically  the 
true  combining  ratio,  z*.  ^.,  I  to  1 .86+. 

The  new  ratio  which  is  sought  to  be  established  is  best  shown 
by  the  formula  3CaO.SiO2,  while  that  for  the  long  accepted  ratio  is 
2CaO.SiO2.  These  two  formulae,  reduced  to  percentages,  are  given 
in  the  order  named. 


UNIVERSITY 

AMERICAN    CEME\TS.  J       93 


Silica     ....     26.38  Silica     ....     34.91 

Lime      ....     73.62  Lime      .     .     .     .     65.09 


Totals     .     .   100.00  100.00 

There  is  no  simpler  way  to  demonstrate  by  practical  experi- 
ment which  of  the  two  formulas  comes  the  nearest  to  actual  facts, 
than  by  mixing  together  clay  and  gypsum,  with  the  latter  in  excess, 
and  calcining  to  a  white  heat.  The  amount  of  sulphate  of  lime 
remaining  will  determine  the  amount  of  lime  that  has  combined  with 
a  given  amount  of  silica. 

Such  experiments  made  under  -the  direction  of  the  author 
demonstrated  very  clearly  that  the  correct  ratio  is  not  in  accord  with 
the  modern  theory  that  3  molecules  of  lime  combine  with  i  of  silica. 

It  is  well  known  that  if  we  calcine  100  pounds  of  gypsum  to  a 
white  heat,  the  only  change  which  is  effected  is  the  expulsion  of  the 
water  of  crystallization,  amounting  to  20.93  per  cent,  of  the  total 
weight,  leaving  79.07  sulphate  of  lime,  which  is  composed  of  lime 
32.55  and  sulphuric  acid  46.52. 

If,  however,  the  100  pounds  of  pure  gypsum  are  finely  ground 
and  thoroughly  mixed  with  23.27  pounds  of  dry  clay,  composed  of 
silica  17.45  and  alumina  5.82  =  23.27  clay,  the  composition  in  hun- 
dred parts  will  be  as  follows :  — 


81.12  gypsum. 


Total     100.00 

If  this  mixture  is  then  calcined  to  a  white  heat,  the  water  of  the 
gypsum  will  first  be  expelled,  and  when  the  high  heat  is  reached,  the 
silicic  acid  will  expel  the  sulphuric  acid  and  itself  combine  with 
the  lime  and  alumina,  forming  an  hydraulic  cement  pure  and  simple, 
the  analysis  of  which  will  appear  in  column  No.  I  of  the  following 
table,  the  succeeding  columns  exhibiting  the  amount  and  kind  of 
silicates  contained  therein. 


Sulphuric  acid 
Lime 
Water 

37-74^ 
26.40  V 
16.98) 

Silica 

14.15 

Alumina 

4-73 

94  AMERICAN    CEMENTS. 

No.  12345 

Silica 31.25  —  18.44  =  12.81  —  12.81=00.00 

Lime 58.30  —  34.39=23.91 — 23.88=00.03 

Alumina 10.45  —  10.45  =  00.00  —  00.00=00.00 


Totals 100.00      63.28  36.69      00.03 

Silicate  of  lime  and  alumina     ....     63.28 
Silicate  of  lime 36.69 


Total  silicates  . 
Total  free  base 


Total 100.00 

It  will  here  be  seen  that,  the  silica  being  present  in  full  combin- 
ing proportions  with  the  lime,  the  sulphuric  acid  was  all  expelled. 
Whereas,  had  there  been  an  excess  of  lime,  it  would  have  retained  its 
equivalent  of  sulphuric  acid  in  combination  as  sulphate  of  lime. 

Now  if  we  deduct  4  from  the  silica,  thus  leaving  the  lime  in 
excess,  the  analysis  before  calcination  would  appear  as  in  the 
following  table. 

Sulphuric  Acid .     39.00"! 

Lime 27.29  I  =83. 84  gypsum. 

Water 17.55] 

Silica 11.28 

Alumina 4.88 


Total 100.00 

After  calcination  at  white  heat,  the  analysis,  reduced  to  hun- 
dreds, will  appear  as  shown  in  column  No.  I  of  the  following  table, 
the  succeeding  columns  showing  the  kind  and  amount  of  silicates 
and  sulphates  in  the  cement. 

No.  12  345 

Sulphuric  Acid      .     .     .     17.10 17.10 

Lime 52.07  —  30.64=21.43 —    9.48=11.95 

Silica 21.52  —  16.43=    5-°9 —    5-°9 


AMERICAN    CEMENTS.  95 

Alumina 9.31  —    9-31=    o.oo —  0.00=    o.oo 

Totals  ....         100.00        56.38  14.57        29.05 

Silicate  of  lime  and  alumina 56.38 

Silicate  of  lime 14.57 

Total  silicates 70.95 

Sulphate  of  lime 29.05 


Total 100.00 

Since  the  days  when  it  became  the  rule  to  add  an  excess  of 
lime  for  the  purposes  stated,  there  have  been  no  artificial  cements 
produced  which  do  not  become  brittle  and  glassy  with  age. 

While  such  a  cement  is  being  used,  and  while  under  the  eye  of 
the  engineer,  and  until  the  work  is  finished  and  has  passed  inspec- 
tion, and  an  occasional  examination  thereafter,  it  seems  to  have 
acted  in  a  most  admirable  and  satisfactory  manner.  It  has  set  hard, 
as  was  expected,  and  the  matter  soon  becomes  ancient  history  with 
the  engineer  or  architect,  whose  attention  is  required  by  things 
present.  And  yet  this  cement  is  not  laid  away  as  though  dead.  It 
is  not  by  any  means  inactive. 

Its  crystallization  is  rapid,  as  evidenced  by  its  prompt  induration, 
and  it  is  this  rapid  crystallization  which  inevitably  results  in  render- 
ing the  mortar  brittle,  and  thereby  liable  to  subsequent  disintegra- 
tion, a  result  which  does  not  follow  in  the  use  of  well-balanced 
American  rock  cements,  which,  although  they  do  not  in  the  earlief 
days  subsequent  to  their  use  exhibit  the  hardness  common  with  the 
artificial  cements,  nevertheless,  at  a  later  period,  reach  the  same 
degree  of  solidity,  and  exhibit  a  toughness  and  tenacity  of  cohesion 
unknown  among  the  modern  artificial  cements. 

Evidence  is  fast  accumulating  which  tends  to  prove  that  all 
cements,  whether  artificial  or  natural,  which  become  brittle  and  glassy 
with  age,  contain  little  or  no  magnesia,  while  those  which  are  tough 
and  stonelike  in  character  do  contain  it ;  and  the  toughness  is  found 
to  be  in  direct  ratio  with  the  amount  of  magnesia  present. 


96  AMERICAN    CEMENTS. 


CHAPTER   VII. 

VARIOUS  METHODS  OF  TESTING  —  ROCK  CEMENTS  IMPROVED  BY 
SEASONING  —  SPECIFICATIONS  BY  U.  S.  ENGINEERS  AND 
OTHERS  —  REPORT  OF  COMMITTEE  TO  A.  S.  C.  E.  ON  UNI- 
FORM SYSTEM  FOR  TESTS  —  CEMENT  TESTING  BY  CECIL  B. 
SMITH  BEFORE  THE  C.  S.  C.  E.  —  PROF.  PORTER  ON  CEMENT 
TESTING  AND  VARYING  RESULTS  BY  DIFFERENT  TESTERS 
—  TESTING  MACHINES  —  OPINIONS  BASED  ON  SHORT  TIME 
TESTS  OFTEN  DECEPTIVE — BRIQUETTES  BECOME  BRITTLE 
WITH  AGE  —  PREDICTION  AS  TO  FUTURE  SPECIFICATIONS  — 
ABSURD  SYSTEM  OF  AVERAGES  —  THE  COLOR  WHIM. 

Early  in  the  present  century,  several  mechanical  contrivances 
were  introduced,  designed  for  the  purpose  of  measuring  the  values 
of  cements. 

Conclusions  were  sought  to  be  reached  by  subjecting  samples  of 
cement,  mortar,  and  concrete  to  various  tests,  among  which  may  be 
named  the  needle  or  penetration  test,  the  transverse,  adhesive,  com- 
pressive,  torsional,  and  tensile  strain  tests,  and  in  later  years  came 
the  boiling  and  freezing  tests. 

The  needle  test,  invented  by  M.  Vicat,  was  perhaps  one  of  the 
earliest,  if  not  the  earliest,  method  employed. 

General  Totten  employed  the  needle  test  at  Fort  Adams,  New- 
port, R.  I.,  for  several  years  prior  to  1830,  and  soon  thereafter  em- 
ployed the  transverse  test. 

It  may  be  stated  that  the  needle  test  was  practised  to  determine 
the  time  in  setting,  and  the  relative  hardness  attained  at  stated 
intervals  during  the  process  of  hardening  of  the  cement  samples. 

As  this  test  did  not  indicate  the  ultimate  strength  of  a  cement, 
or  a  cement  mortar,  it  soon  gave  place  to  the  transverse  and  the  ad- 
hesive tests. 


AMERICAN    CEMENTS.  97 

General  Gillmore  employed  the  needle,  the  transverse,  the  ten- 
sile, and  the  adhesive  tests  prior  to  1860. 

Briefly,  these  tests  may  be  described  as  follows :  — 

The  relative  hardness  of  the  samples  at  stated  intervals  during 
and  after  the  process  of  setting  was  measured  by  the  penetration  of 
a  steel  point  or  needle  impelled  by  the  impact  of  a  falling  body. 

The  transverse  test  consisted  in  the  molding  of  cement  or  cement 
mortar  into  prisms  or  bars  usually  2  ins.  by  2  ins.  by  8  ins.,  under  pres- 
sure, which,  after  setting,  were  placed  in  water,  and  after  a  specified 
number  of  days  had  elapsed  were  broken  by  being  placed  on  supports 
4  ins.  apart,  and  a  pressure  brought  to  bear  midway  between  the 
supports. 

The  adhesive  properties  of  a  cement  were  measured  by  cement- 
ing bricks  and  blocks  of  stone  together  in  pairs  under  pressure 
during  the  time  of  setting,  and  afterwards  drawing  them  apart  by  a 
force  applied  at  right  angles  to  the  plane  of  the  joint. 

The  tensile  test  was  practically  the  same  as  that  now  in  vogue ; 
the  form  of  the  briquettes,  and  the  machines  for  conducting  the  tests 
named,  have  changed  considerably,  but  the  principles  involved  are 
practically  unaltered. 

The  transverse  and  compressive  tests  are  still  occasionally  resorted 
to,  but  the  torsional  and  adhesive  tests  are  no  longer  practised  to  any 
extent. 

Between  1850  and  1860,  the  mode  of  testing  cements  by  means 
of  the  tensile-strain  testing  machines  gained  largely  in  public  favor 
in  France,  and  was  soon  followed  by  a  like  tendency  in  England. 

It  was  adopted  by  the  Metropolitan  Board  of  Works  in  London 
in  1859,  and  under  the  supervision  of  Engineers  Grant,  Bazalgette, 
Colson,  Mann  and  others,  soon  became  considered  as  a  valuable 
adjunct  in  the  determination  of  the  qualities  of  the  various  cements 
offered  on  that  work. 

From  that  time  until  the  present,  the  tensile-strain  method  of 
testing  cements  has  constantly  grown  in  public  favor,  and  has  be- 
come the  universal  practise  among  engineers,  architects,  and  manu- 
facturers. 

Why  this  mode  of  testing  the  strength  of  cements  and  cement 
mortars  survived  almost  to  the  exclusion  of  the  others,  it  is  hard  to 
determine. 


98  AMERICAN    CEMENTS. 

It  certainly  cannot  compare  with  the  transverse  test  for  simplicity 
of  machinery  or  accuracy  of  results. 

In  the  formation  of  the  samples  to  be  tested  for  the  transverse 
tests,  the  prisms,  being  straight,  uniform  bodies,  could  be  readily 
subjected  to  any  predetermined  pressure,  and  the  density  of  the 
prisms  be  gaged  to  a  degree  of  uniformity  unattainable  in  the  modern 
briquette. 

Cement  testing,  although  practised  now  much  more  than  formerly, 
is  still  far  from  being  reduced  to  any  fixed  system  of  rules. 

Each  engineer  or  architect  is  a  law  unto  himself,  and  United 
States  engineers  even,  do  not  seem  to  be  governed  by  any  one  stand- 
ard, and  it  would  be  difficult  to  find  a  brand  of  cement  which  could 
fulfil  all  the  requirements  of  the  various  specifications  which  are 
from  time  to  time  given  out  to  the  manufacturers. 

Thus,  for  example,  one  set  of  specifications  states  that  "  the 
cement  must  be  freshly  burned,"  but,  "  must  not  take  less  than  twenty- 
five  minutes  to  bear  the  light  wire,  that  is,  a  weight  of  four  ounces 
on  a  wire  one  twelfth  of  an  inch  in  diameter." 

Now  nearly  all  of  our  best  brands  of  rock  cements  will  bear  the 
light  wire  in  about  one  half  of  the  time  specified,  if  tested  when  fresh, 
but  will  fulfil  the  requirements  if  they  have  had  time  to  season. 

Much  also  depends  on  the  amount  of  water  used,  as  the  initial 
set  can  be  retarded  by  a  trifling  addition  of  water,  or  hastened  by 
using  just  enough  to  enable  the  cement  to  be  molded. 

But  in  this,  as  in  many  other  matters  connected  with  the  testing 
of  a  cement,  the  manufacturer  has  nothing  to  say.  He  is  at  the 
mercy  of  the  engineer,  and  engineers  who  are  willing  to  accept  sug- 
gestions from  the  manufacturers  are  not  as  thick  as  autumn  leaves 
in  Vallombrosa. 

It  is  certain  that  all  the  best  brands  of  rock  cements  in  this 
country  are  improved  by  one  or  two  months  of  seasoning,  and  all  this 
that  we  read  about,  to  the  effect  that  rock  cements  must  be  used 
immediately  after  manufacture,  lest  deterioration  may  set  in,  is  arrant 
nonsense. 

The  author  is  familiar  with  every  brand  of  rock  cement  produced 
in  this  country,  and  he  does  not  know  of  one  brand  that  is  not  im- 
proved by  one  to  two  months'  exposure. 

The  manufacturers  understand  this,  for,  to  learn  the  value  of 


AMERICAN    CEMENTS.  99 

seasoning,  they  have  but  to  set  aside  a  tightly  closed  package  filled 
fresh  from  the  mill  spout,  and  take  some  from  the  same  grinding 
and  spread  it  in  a  dry  place  where  the  air  has  free  access  to  it,  and 
at  the  end  of  thirty  or  sixty  days  test  both  samples. 

And  yet  they  are  daily  confronted  with  specifications  stipulating 
that  the  cement  must  be  freshly  burned. 

Some  of  the  very  best  brands  of  rock  cements  in  this  country 
are  vastly  improved  by  four  months'  exposure,  if  kept  on  floors  high 
enough  from  the  ground  to  preclude  the  possibility  of  the  absorption 
of  moisture  from  below. 

A  rock  cement  which  is  not  improved  by  an  exposure  of  from 
thirty  to  sixty  days  can  hardly  be  considered  a  strictly  first-class 
cement. 

There  are  several  of  our  best  brands  of  rock  cements  that  are 
naturally  moderate  in  setting  when  given  even  a  brief  exposure,  yet 
when  tested  fresh,  will  take  a  rapid  surface  hardening  and  give  every 
appearance  of  being  naturally  quick  setting ;  but  an  examination  of 
the  fracture  of  briquettes  made  from  such  cements  will  disclose  the 
fact  that  at  twenty-four  hours  crystallization  has  barely  commenced, 
thus  giving  evidence  of  not  too  rapid  setting.  Still  the  superficial 
hardening,  due  to  freshness,  will  cause  them  to  bear  the  light  wire 
too  soon  to  bring  them  within  the  specifications. 

In  this  way  it  oftentimes  happens  that  a  really  first-class  cement 
may  be  rejected  because  it  sustains  the  light  wire  too  soon. 

The  author  has  seen  a  fresh  cement  rejected  because  it  bore 
the  wire  too  soon,  and  the  sample  set  aside,  and  after  a  few  days 
had  elapsed,  tested  again  from  mere  curiosity,  and  found  to  be  slow 
enough  to  come  within  the  specifications. 

During  the  few  days  of  exposure  the  peculiarity  noted  had 
entirely  disappeared. 

Specifications  governing  cement  tests,  derived  from  various 
authentic  sources,  are  herewith  given  :  — 

U.  S.  ENGINEER  OFFICE, 
PORTLAND,  MAINE,  Feb.  14,  1893. 
PETER  C.  HAINS,  LIEUT.-COL.  OF  ENGINEERS. 

The  cement  is  to  be  hydraulic,  uniform  in  quality,  fresh,  dry,  finely 


100  AMERICAN    CEMENTS. 

ground,  free  from  lumps,  and  put  up  in  good  sound  barrels,  each 
barrel  of  cement  to  weigh  not  less  than  300  Ibs.  net.  A  sample  is  to 
be  submitted  for  test,  and  the  entire  quantity  delivered  must  be  fully 
up  to  the  sample. 

The  cement  must  not  set  within  twenty  minutes.  Briquettes 
made  of  neat  cement,  mixed  with  a  proper  proportion  of  water,  must 
show  a  tensile  strength  per  square  inch  of  not  less  than  60  Ibs.  after 
exposure  to  the  air  for  twenty-four  hours ;  kept  one  day  in  air  and 
six  in  water,  not  less  than  100  Ibs.;  and  kept  one  day  in  air  and 
twenty-seven  in  water,  not  less  than  1 80  Ibs. 

At  least  90  per  cent,  must  pass  through  a  sieve  of  2,500  meshes 
to  the  square  inch. 

The  cement  will  be  subjected  to  such  other  tests  as  the  engineer 
may  deem  necessary. 

U.  S.  ENGINEER  OFFICE, 
ARMY  BUILDING,  39  WHITEHALL  STREET, 
NEW  YORK,  N.  Y.,  Jan.  25,  1893. 

G.  L.  GlLLESPIE,  LlEUT.-COL.    CORPS    OF    ENGINEERS. 

The  cement  will  be  of  first  quality  American  cement,  fresh,  dry, 
full  weight,  finely  ground,  free  from  lumps,  and  put  up  in  good  sound 
barrels. 

The  bids  will  state  the  special  brand  proposed  to  be  furnished, 
and  the  bidder  will  deliver  a  sample  barrel  upon  Pier  3,  East  River, 
for  test,  at  least  ten  days  before  the  opening  of  the  bids. 

The  cement  will  be  expected  to  stand  the  following  tests :  Ce- 
ment neat  must  be  set  in  about  thirty  minutes,  and  have  tensile 
strength  per  square  inch  as  follows :  — 

Samples  which  have  been  kept  in  air  and  broken  at  twenty-four 
hours  after  setting,  70  Ibs. ;  at  seven  days,  125  Ibs. ;  at  fourteen  days, 
170  Ibs.;  and  at  thirty  days,  225  Ibs. 

Samples  which  have  been  kept  twenty-four  hours  in  air  and 
then  in  water  until  broken :  at  twenty-four  hours,  70  Ibs. ;  at  seven 
days,  90  Ibs. ;  at  fourteen  days,  120  Ibs. ;  and  at  thirty  days,  150  Ibs. 

Cement  one  part,  sand  two  parts,  tensile  strength  per  square 
inch,  samples  kept  in  air  until  broken  :  at  twenty-four  hours,  1 5  Ibs. ; 
at  seven  days,  35  Ibs. ;  at  fourteen  days,  50  Ibs. ;  and  at  thirty  days, 
65  Ibs. ;  and  immersed  in  water  twenty-four  hours  after  setting :  at 


AMERICAN    CEMENTS.  101 

twenty-four  hours,  1 5  Ibs. ;    at  seven  days,  30  Ibs. ;  at  fourteen  days, 
45  Ibs. ;    and  at  thirty  days,  65  Ibs. 

U.  S.  ENGINEER  OFFICE, 

CUSTOM  HOUSE,  PITTSBURGH,  PENN.,  July  31,  1894. 
CAPT.  R.  L.  HOXIE,  CORPS  OF  ENGINEERS,  U.  S.  A. 

AMERICAN    HYDRAULIC   CEMENT. 

INSPECTION. —  Ten  per  cent,  of  the  packages  in  each  car-load, 
and  no  more,  will  be  selected  for  weighing  and  testing.  The 
weight  and  quality  of  all  cement  in  each  car-load  will  be  determined 
by  weighing  and  testing  these  selected  packages.  The  average  net 
weight  of  all  packages  in  each  car-load  lot  will  be  the  average  net 
weight  of  all  the  selected  packages.  The  failure  of  any  one  of  the 
selected  packages  to  stand  the  required  tests  will  be  sufficient  reason 
for  rejecting  this  car-load  lot,  excepting  only  those  packages  which 
may  have  stood  the  test.  Rejected  cement  will  be  immediately  re- 
shipped  to  the  contractor  at  his  expense,  and  the  cost  of  all  han- 
dling of  same  will  be  charged  against  his  account. 

FINENESS. —  Ninety-five  per  cent,  by  weight  must  pass  through 
a  cement  wire  sieve  having  2,500  meshes  per  square  inch,  and  made 
of  No.  35  wire,  Stubb's  W.  G. 

PREPARATION  OF  TEST  BRIQUETTES. —  Cement  will  be  mixed 
neat,  with  enough  water  only  to  thoroughly  moisten  and  make  it 
coherent,  and  will  be  pressed  into  the  mold  with  a  spatula.  Tem- 
perature not  below  60°. 

SETTING. —  The  surface  must  yield  to  the  pressure  of  a  wire 
2\  in.  diameter,  carrying  a  weight  of  i  Ib.  thirty  minutes  after  com- 
pletion of  briquette. 

TENSILE  STRENGTH  PER  SQUARE  INCH  OF  CROSS-SECTION. 
—  This  will  be  for  each  package  the  average  strength  of  five  bri- 
quettes. These  will  be  kept  in  air  until  set,  and  then  immersed  in 
water  until  they  are  put  into  the  clips  of  the  testing  machine,  being 
tested  wet.  After  twenty-four  hours'  immersion  in  water,  the  tensile 
strength  must  be  70  Ibs.,  and  after  seven  days'  immersion,  125  Ibs. 

CHECKING  AND  CRACKING. —  When  made  into  a  thin  cake, 
allowed  to  set  in  air,  and  immersed  in  water,  no  checking  or  cracking 
must  be  shown. 


102  AMERICAN   CEMENTS. 

Specifications  for  the  cement  used  in  the  masonry  of  the  de- 
pressed Harlem  Railroad  tracks  in  New  York  City. 

The  cement  must  be  of  the  best  quality  of  freshly  burned  and 
ground  hydraulic  cement.  It  will  be  subject  to  test  made  by  the 
engineer  or  his  appointed  inspector,  and  must  stand  a  proof  tensile 
test  of  50  Ibs.  per  square  inch  of  sectional  area  on  specimens  mixed 
to  a  stiff  paste  and  allowed  a  set  of  thirty  minutes  in  air  and  twenty- 
four  hours  under  water ;  and  of  90  Ibs.  on  specimens  allowed  a  set 
of  seven  days  under  water,  and  shall  be  90  per  cent,  fine  when  tried 
with  a  sieve  of  2,500  meshes  to  the  square  inch. 

It  must  take  not  less  than  twenty-five  minutes  to  bear  the  light 
wire  —  that  is,  a  weight  of  4  ozs.  on  a  wire  one  twelfth  of  an  inch  in 
diameter. 

The  following  specifications  for  hydraulic  cement  were  drawn 
by  a  United  States  engineer  who  advertised  for  a  large  amount  of 
cement  and  received  but  one  bid. 

The  cement  must  possess  the  following  requisites  :  — 

FIRST. —  It  must  be  fresh,  slow  setting,  and  so  finely  ground  that 
85  per  cent,  of  it  shall  pass  through  a  sieve  of  2,500  meshes  per 
square  inch. 

SECOND. —  After  being  mixed  neat  and  filled  into  a  glass  bottle, 
or  similar  vessel,  and  struck  level  with  the  top,  it  must  not  crack  the 
vessel  in  setting,  nor  rise  out  of  it,  nor  become  loose  in  it  by  shrink- 
age. 

THIRD. —  When  mixed  neat  and  made  up  into  briquettes,  and 
given  one  hour  in  air,  then  twenty-three  hours  in  water,  the  cement 
must  be  capable  of  withstanding  a  tensile  strain  of  35  Ibs.  per  square 
inch  before  it  is  fractured ;  and  after  seven  days  in  water,  succeed- 
ing the  first  hour  in  air,  it  must  sustain  a  tensile  strain  of  125  Ibs. 
per  square  inch. 

FOURTH. —  Its  initial  setting  shall  not  take  place  in  less  than 
thirty  minutes  from  the  time  it  is  mixed  neat  into  a  paste. 

FIFTH. —  The  cement  must  possess  reliable  uniformity  of  all 
these  qualities. 

It  will  be  noted  that  these  specifications  state  that  "  the  cement 
must  be  fresh,"  and  yet,  "  the  initial  set  must  not  take  place  in  less 
than  thirty  minutes." 


AMERICAN   CEMENTS.  103 

It  is  doubtful  if  any  brand  of  rock  cement  could  fulfil  all  the 
requirements. 

The  following  letter  is  in  reply  to  an  inquiry  by  the  author :  — 

TREASURY  DEPARTMENT, 
OFFICE  OF  THE  SUPERVISING  ARCHITECT, 
WASHINGTON,  D.  C.,  May  14,  1896. 

Sir:  —  Replying  to  your  letter  of  the  nth  inst.,  you  are  in- 
formed that  the  requirements  of  cement  to  be  used  under  this  office 
are  as  follows  :  — 

Hydraulic  cement,  mixed  neat,  one  day  in  air  and  six  days  in 
water,  should  stand  a  tensile  strain  of  90  Ibs.  per  square  inch. 

Portland  cement,  mixed  neat,  one  day  in  air  and  six  days  in 
water,  should  stand  a  tensile  strain  of  350  Ibs.  pefsquare  inch. 

This  office  has  no  printed  forms  governing  the  making  of  mor- 
tars and  concretes ;  specifications  for  this  class  of  work  vary  accord- 
ing to  circumstances. 

Respectfully  yours, 

(Signed)  WM.  M.  AIKEN, 

Supervising  Architect. 

1895, 

DEPARTMENT  OF  PUBLIC  WORKS, 
PEORIA,  ILLINOIS. 

ALMON  D.  THOMPSON,  CITY  ENGINEER. 

All  cement  for  concrete  foundations  shall  be  what  is  commonly 
known  as  American  Natural  Hydraulic  Cement,  of  quality  equal  to 
the  best  obtainable  in  the  markets.  All  Portland  cement  used  on 
the  work  shall  be  the  best  obtainable  in  the  markets.  They  will  be 
subjected  to  rigid  inspection,  and  that  rejected  shall  be  immediately 
removed  by  the  contractor. 

The  contractor  must  submit  the  cement  for  inspection  and  test- 
ing at  least  ten  days  before  using,  and  such  inspection  and  tests  will 
be  made  only  from  samples  obtained  by  the  inspector  from  cement 
delivered  on  the  work. 


104  AMERICAN    CEMENTS. 

The  inspector  shall  be  notified  of  each  delivery  of  cement.  All 
cement  must  stand  the  following  tests :  — 

Two  cakes,  3  ins.  in  diameter  and  ^  in.  thick,  with  thin  edges, 
will  be  made. 

One  of  these  cakes  as  soon  as  set  will  be  placed  in  water  and 
examined  from  day  to  day.  If  the  cake  exhibits  checks,  cracks,  or 
contortions,  the  cement  will  be  rejected.  The  other  cake  described 
will  be  used  for  setting  and  color  tests. 

The  time  will  be  noted  when  the  cake  has  become  hard  enough 
to  sustain  a  wire  ^  in.  in  diameter  loaded  with  %  Ib. 

When  the  wire  is  sustained,  the  cement  has  begun  to  set,  and 
this  time  shall  not  be  less  than  ten  minutes  for  natural  cement,  nor 
less  than  forty-five  minutes  for  Portland  cement. 

When  the  cake  will  sustain  a  wire  fa  in.  in  diameter  loaded  with 
i  Ib.,  the  set  is  complete,  and  this  time  must  not  be  less  than  one 
hour  nor  more  than  three  hours  for  natural  cement,  nor  less  than 
two  hours  nor  more  than  six  hours  for  Portland  cement. 

The  cake  used  for  setting  test  will  be  preserved,  and  when  exam- 
ined from  day  to  day  must  be  of  uniform  color,  exhibiting  no  blotches 
or  discolorations. 

The  cement  must  be  evenly  ground,  and,  when  tested  with  the 
following  standard  sieves,  must  pass  at  least  the  following  percent- 
ages:— 

Natural.        Portland. 

No.  20  sieve,  having  20  meshes  per  lineal  inch  .  100% 

No.  50  sieve,  having  50  meshes  per  lineal  inch  .  90%  98% 

No.  74  sieve,  having  74  meshes  per  lineal  inch  .  80%  94% 

No.  i  oo  sieve,  having  i  oo  meshes  per  lineal  inch  .  90% 

The  diameter  of  wire  for  sieves  being  respectively :  — 

For  No.  20  sieve,  No.  28  Stubb's  wire  gauge. 
For  No.  50  sieve,  No.  35  Stubb's  wire  gauge. 
For  No.  74  sieve,  No.  37  Stubb's  wire  gauge. 
For  No.  100  sieve,  No.  40  Stubb's  wire  gauge. 

All  cement  for  test  briquettes  will  be  mixed  with  barely  sufficient 
water  to  make  a  stiff  mortar. 


AMERICAN    CEMENTS.  105 

The  neat  briquettes  to  be  pressed  into  the  molds  by  hand  and 
the  sand  briquettes  to  be  compacted  by  light  tapping. 

The  sand  for  cement  tests  will  be  crushed  quartzite  of  such 
fineness  that  all  will  pass  a  sieve  of  20  meshes  per  lineal  inch,  and 
none  of  it  a  sieve  of  30  meshes  per  lineal  inch. 

The  required  tensile  strength  per  square  inch  shall  be  as  fol- 
lows : — 

Neat  Cement.  Natural.     Portland. 

One  day,  till  set  in  air,  remainder  of  time  in  water  .     60  Ibs.  1 50  Ibs. 
One  week,  one  day  in  air,  six  days  in  water   .     .     .150  Ibs.  400  Ibs. 

CEMENT  ONE  PART  AND  SAND  TWO  PARTS. 

One  week  —  one  day  in  air,  six  days  in  water    .     .     75  Ibs. 

CEMENT  ONE  PART  AND  SAND  ONE  AND  ONE  HALF  PARTS. 

One  week  —  one  day  in  air,  six  days  in  water  .     .     85  Ibs. 

CEMENT  ONE  PART  AND  SAND  THREE  PARTS. 

One  week — one  day  in  air,  six  days  in  water 140  Ibs. 

Briquettes  for  the  seven-day  tests  shall  be  covered  for  the  first 
twenty-four  hours  with  a  damp  cloth. 

The  specifications  covering  the  use  of  cement  on  the  new  Croton 
aqueduct  for  New  York  City,  and  drawn  by  the  chief  engineer,  Benj. 
S.  Church,  1884,  were  as  follows  :  — 

"  The  greater  part  of  the  masonry  is  to  be  laid  in  American 
cement  mortar,  but  Portland  cement  is  to  be  used  whenever  directed. 

"  The  American  cement  must  be  equal  in  quality  to  the  best 
Rosendale  cement ;  it  must  be  made  by  manufacturers  of  established 
reputation ;  must  be  fresh  and  very  fine  ground,  and  in  well-made 
casks. 

"  The  Portland  cement  must  be  of  a  brand  equal  in  quality  to 
the  best  English  Portland  cement. 

"To  insure  its  good  quality,  all  the  cement  furnished  by  the 
contractor  will  be  subject  to  inspection  and  rigorous  tests;  and  if 
found  of  improper  quality  will  be  branded,  and  must  be  immediately 


106  AMERICAN   CEMENTS. 

removed  from  the  work ;  the  character  of  the  tests  to  be  determined 
by  the  engineer. 

"  The  contractor  shall  at  all  times  keep  in  store,  at  some  con- 
venient point  in  the  vicinity  of  the  work,  a  sufficient  quantity  of 
cement  to  allow  ample  time  for  the  tests  to  be  made  without  delay  to 
the  work  of  construction. 

"  The  engineer  shall  be  notified  at  once  of  each  delivery  of 
cement.  It  shall  be  stored  in  a  tight  building,  and  each  cask  must  be 
raised  several  inches  above  the  ground  by  blocking  or  otherwise." 

The  tests  employed  on  the  line  of  the  aqueduct  were  those 
recommended  by  the  American  Society  of  Civil  Engineers,  which  are 
herewith  given. 

AMERICAN    SOCIETY    OF   CIVIL   ENGINEERS. 

REPORT   OF   THE    COMMITTEE   ON    A    UNIFORM    SYSTEM    FOR   TESTS    OF 

CEMENT. 

PRESENTED  AT  THE  ANNUAL  MEETING,  JAN.  21,  1885. 
To  the  American  Society  of  Civil  Engineers :  — 

Your  committee,  appointed  to  devise  a  uniform  system  for  tests  of 
hydraulic  cement,  has  the  honor  to  submit  this  final  report.  Those 
portions  of  the  preliminary  report  presented  at  the  annual  meeting  held 
Jan.  1 6,  1884,  which  are  not  embodied  herein,  are  superseded. 

A  uniform  system  of  testing  cement,  in  order  to  be  practical,  must  be 
simple,  rapid,  and  easy  of  application,  and  should,  of  course,  be  reasonably 
accurate.  Between  the  very  careful  tests  of  the  laboratory,  which  consume 
much  time  and  involve  considerable  expense,  and  the  rough  and  unsatis- 
factory trials  often  resorted  to  from  necessity,  there  is  a  middle  ground, 
which  it  has  been  the  endeavor  of  the  committee  to  occupy.  The  system 
proposed  is  by  no  means  a  perfect  one — such  has  not  yet  been  dis- 
covered—  but  it  is  hoped  that  it  will  be  useful  in  eliminating  many  of  the 
inaccuracies  of  the  usual  methods,  and  by  making  the  system  uniform, 
enable  the  experiments  of  the  various  members  of  the  profession,  in 
different  parts  of  the  country,  and  others  interested  in  the  subject  of 
cement  testing,  to  be  satisfactorily  compared. 

The  testing  of  cement  is  not  so  simple  a  process  as  it  is  sometimes 
thought  to  be.  No  small  degree  of  experience  is  necessary  before  one  can 
manipulate  the  materials  so  as  to  obtain  even  approximately  accurate 
results. 


AMERICAN    CEMENTS.  107 

The  first  test  of  inexperienced,  though  intelligent  and  careful  persons, 
are  usually  very  contradictory  and  inaccurate,  and  no  amount  of  experi- 
ence can  eliminate  the  variations  introduced  by  the  personal  equations  of 
the  most  conscientious  observers.  Many  things,  apparently  of  minor 
importance,  exert  such  a  marked  influence  upon  the  results,  that  it  is  only 
by  the  greatest  care  in  every  particular,  aided  by  experience  and  intelligence, 
that  trustworthy  tests  can  be  made. 

The  test  for  tensile  strength  on  a  sectional  area  of  one  square 
inch  is  recommended,  because,  all  things  considered,  it  seems  best  for  gen- 
eral use.  In  the  small  briquette  there  is  less  danger  of  air  bubbles,  the 
amount  of  material  to  be  handled  is  smaller,  and  the  machine  for  breaking 
may  be  lighter  and  less  costly. 

The  tensile  test,  if  properly  made,  is  a  good,  though  not  a  perfect  in- 
dication of  the  value  of  a  cement.  The  time  requisite  for  making  this 
test,  whether  applied  to  either  the  natural  *  or  the  Portland  cements,  is 
considerable  (at  least  seven  days,  if  a  reasonably  reliable  indication  is  to 
be  obtained),  and  as  work  is  usually  carried  on,  is  frequently  impracticable. 
For  this  reason  short  time  tests  are  allowable  in  cases  of  necessity,  though 
the  most  that  can  be  done  in  such  testing  is  to  determine  if  the  brand  of 
cement  is  of  its  average  quality.  It  is  believed,  however,  that  if  a  neat 
cement  stands  the  one-day  tensile  test,  and  the  tests  for  checking  and  for 
fineness,  its  safety  for  use  will  be  sufficiently  indicated  in  the  case  of  a 
brand  of  good  reputation ;  for,  it  being  proved  to  be  of  average  quality, 
it  is  fair  to  suppose  that  its  subsequent  condition  will  be  what  former 
experiments,  to  which  it  owes  its  reputation,  indicate  that  it  should  be.  It 
cannot  be  said  that  a  new  and  untried  cement  will  by  the  same  tests  be 
proved  to  be  satisfactory ;  only  a  series  of  tests  for  a  considerable  period, 
and  writh  a  full  dose  of  sand,  will  show  the  full  value  of  any  cement ;  and 
it  would  be  safer  to  use  a  trustworthy  brand,  without  applying  any  tests 
whatever,  than  to  accept  a  new  article  which  had  been  tested  only  as 
neat  cement  and  for  but  one  day. 

The  test  for  compressive  strength  is  a  very  valuable  one  in  point  of 
fact,  but  the  appliances  for  crushing  are  usually  somewhat  cumbersome 
and  expensive,  so  much  so  that  it  seems  undesirable  that  both  tests  should 
be  embodied  in  a  uniform  method  proposed  for  general  adoption.  Where 
great  interests  are  at  stake,  however,  and  large  contracts  for  cement  depend 
on  the  decision  of  an  engineer  as  to  quality,  both  tests  should  be  used  if 
the  requisite  appliances  for  making  them  are  within  reach.  After  the 

*  Where  the  word  "  natural "  is  used  in  this  connection,  it  is  to  be  understood  as  being 
applied  to  the  lightly  burned  natural  American  or  foreign  cements,  in  contradistinction  to 
the  more  heavily  burned  Portland  cement,  either  natural  or  artificial. 


108  AMERICAN    CEMENTS. 

tensile  strength  has  been  obtained,  the  ends  of  the  broken  briquettes, 
reduced  to  one-inch  cubes  by  grinding  and  rubbing,  should  be  used  to 
obtain  the  compressive  strength. 

The  adhesive  test  being  in  a  large  measure  variable  and  uncertain, 
and,  therefore,  untrustworthy,  is  not  recommended. 

FINENESS. 

The  strength  of  a  cement  depends  greatly  upon  the  fineness  to  which 
it  is  ground,  especially  when  mixed  with  a  large  dose  of  sand.  It  is, 
therefore,  recommended  that  the  test  be  made  with  cement  that  has 
passed  through  a  No.  100  sieve  (10,000  meshes  to  the  square  inch),  made 
of  No.  40  wire,  Stubbs's  wire  gauge.  The  results  thus  obtained  will  in- 
dicate the  grade  which  the  cement  can  attain,  under  the  condition  that  it 
is  finely  ground,  but  it  does  not  show  whether  or  not  a  given  cement  offered 
for  sale  shall  be  accepted  and  used.  The  determination  of  this  question 
requires  that  the  tests  should  also  be  applied  to  the  cement  as  found  in  the 
market.  Its  quality  may  be  so  high  that  it  will  stand  the  tests  even  if  very 
coarse  and  granular,  and,  on  the  other  hand,  it  may  be  so  low  that  no 
amount  of  pulverization  can  redeem  it.  In  other  words,  fineness  is  no  sure 
indication  of  the  value- of  a  cement,  although  all  cements  are  improved  by 
fine  grinding.  Cement  of  the  better  grades  is  now  usually  ground  so  fine 
that  only  from  5  to  10  per  cent,  is  rejected  by  a  sieve  of  2,500  meshes  per 
square  inch,  and  it  has  been  so  fine  that  only  from  3  to  10  per  cent,  is  re- 
jected by  a  sieve  of  32,000  meshes  per  square  inch.  The  finer  the  cement, 
if  otherwise  good,  the  larger  dose  of  sand  it  will  take,  and  the  greater  its 
value. 

CHECKING   OR    CRACKING. 

The  test  for  checking  or  cracking  is  an  important  one,  and,  though 
simple,  should  never  be  omitted.  It  is  as  follows  :  — 

Make  two  cakes  of  neat  cement  2  or  3  ins.  in  diameter,  about  ^  in. 
thick,  with  thin  edges.  Note  the  time  in  minutes  that  these  cakes,  when 
mixed  with  water  to  the  consistency  of  a  stiff  plastic  mortar,  take  to  set 
hard  enough  to  stand  the  wire  test  recommended  by  General  Gilmore,  -fa 
in.  diameter  wire  loaded  with  ^  of  a  lb.,  and  ^  in.  loaded  with  I  Ib. 
One  of  these  cakes,  when  hard  enough,  should  be  put  in  water,  and  ex- 
amined from  day  to  day  to  see  if  it  becomes  contorted,  or  if  cracks  show 
themselves  at  the  edges,  such  contortions  or  cracks  indicating  that  the 
cement  is  unfit  for  use  at  that  time.  In  some  cases  the  tendency  to  crack, 
if  caused  by  the  presence  of  too  much  unslacked  lime,  will  disappear  with 
age.  The  remaining  cake  should  be  kept  in  the  air  and  its  color  observed, 
which  for  a  good  cement  should  be  uniform  throughout,  yellowish  blotches 


AMERICAN    CEMENTS.  109 

indicating  a  poor  quality  ;  the  Portland  cements  being  of  a  bluish  gray, 
and  the  natural  cements  being  light  or  dark,  according  to  the  character  of 
the  rock  of  which  they  are  made.  The  color  of  the  cements  when  left  in 
the  air  indicates  the  quality  much  better  than  when  they  are  put  in  water. 

TESTS    RECOMMENDED. 

It  is  recommended  that  tests  for  hydraulic  cement  be  confined  to 
methods  for  determining  fineness,  liability  to  checking  or  cracking,  and 
tensile  strength ;  and  for  the  latter,  for  tests  of  seven  days  and  upward, 
that  a  mixture  of  i  part  of  cement  to  I  part  of  sand  for  natural  cements, 
and  3  parts  of  sand  for  Portland  cements,  be  used,  in  addition  to  trials  of 
the  neat  cement.  The  quantities  used  in  the  mixture  should  be  determined 
by  weight. 

The  tests  should  be  applied  to  the  cements  as  offered  for  sale.  If 
satisfactory  results  are  obtained  with  a  full  dose  of  sand,  the  trials  need 
go  no  further.  If  not,  the  coarser  particles  should  first  be  excluded  by 
using  a  No.  i oo  sieve,  in  order  to  determine  approximately  the  grade  the 
cement  would  take  if  ground  fine,  for  fineness  is  always  attainable,  while 
inherent  merit  may  not  be. 

MIXING,    ETC. 

The  proportions  of  cement,  sand,  and  water  should  be  carefully  de- 
termined by  weight,  the  sand  and  cement  mixed  dry,  and  all  the  water 
added  at  once.  The  mixing  must  be  rapid  and  thorough,  and  the  mortar, 
which  should  be  stiff  and  plastic,  should  be  firmly  pressed  into  the  molds 
with  the  trowel,  without  ramming,  and  struck  off  level ;  the  molds  in  each 
instance,  while  being  charged  and  manipulated,  to  be  laid  directly  on  glass, 
slate,  or  some  other  non-absorbent  material.  The  molding  must  be  com- 
pleted before  incipient  setting  begins.  As  soon  as  the  briquettes  are  hard 
enough  to  bear  it,  they  should  be  taken  from  the  molds  and  be  kept  covered 
with  a  damp  cloth  until  they  are  immersed.  For  the  sake  of  uniformity, 
the  briquettes,  both  of  neat  cement  and  those  containing  sand,  should  be 
immersed  in  water  at  the  end  of  twenty-four  hours,  except  in  the  case  of 
one-day  tests. 

Ordinary  fresh,  clean  water,  having  a  temperature  between  60  and  70 
degrees  F.,  should  be  used  for  the  water  of  mixture  and  immersion  of 
samples. 

The  proportion  of  water  required  varies  with  the  fineness,  age,  or 
other  conditions  of  the  cement,  and  the  temperature  of  the  air,  but  is 
approximately  as  follows  :  — 

For  briquettes  of  neat  cement :  Portland,  about  25  per  cent. ;  natural, 
about  30  per  cent. 


110  AMERICAN   CEMENTS. 

For  briquettes  of  I  part  cement,  i  part  sand;  about  15  per  cent,  of 
total  weight  of  sand  and  cement. 

For  briquettes  of  i  part  cement,  3  parts  sand;  about  12  per  cent,  of 
total  weight  of  sand  and  cement. 

The  object  is  to  produce  the  plasticity  of  rather  stiff  plasterer's 
mortar. 

An  average  of  five  briquettes  may  be  made  for  each  test,  only  those 
breaking  at  the  smallest  section  to  be  taken.  The  briquettes  should 
always  be  put  in  the  testing  machine  and  broken  immediately  after  being 
taken  out  of  the  water,  and  the  temperature  of  the  briquettes  and  of  the 
testing  room  should  be  constant  between  60  and  70  degrees  F. 

The  stress  should  be  applied  to  each  briquette  at  a  uniform  rate  of 
about  400  Ibs.  per  minute,  starting  each  time  at  o.  With  a  weak  mixture 
one  half  the  speed  is  recommended. 

WEIGHT. 

The  relation  of  the  weight  of  cement  to  its  tensile  strength  is  an  un- 
certain one.  In  practical  work,  if  used  alone,  it  is  of  little  value  as  a  test, 
while  in  connection  with  the  other  tests  recommended  it  is  unnecessary, 
except  when  the  relative  bulk  of  equal  weights  of  cement  is  desired. 

We  recommend  that  the  cubic  foot  be  substituted  for  the  bushel  as 
the  standard  unit,  whenever  it  is  thought  best  to  use  this  test. 

SETTING. 

The  rapidity  with  which  a  cement  sets  or  loses  its  plasticity  furnishes 
no  indication  of  its  ultimate  strength.  It  simply  shows  its  initial  hydraulic 
activity. 

For  purposes  of  nomenclature,  the  various  cements  may  be  divided 
arbitrarily  into  two  classes,  namely :  quick-setting,  or  those  that  set  in  less 
than  half  an  hour;  and  slow-setting,  or  those  requiring  half  an  hour  or  more 
to  set.  The  cement  must  be  adapted  to  the  work  required,  as  no  one 
cement  is  equally  good  for  all  purposes.  In  submarine  work  a  quick- 
setting  cement  is  often  imperatively  demanded,  and  no  other  will  answer, 
while  for  work  above  the  water-line  less  hydraulic  activity  will  usually  be 
preferred.  Each  individual  case  demands  special  treatment.  The  slow- 
setting  natural  elements  should  not  become  warm  while  setting,  but  the 
quick-setting  ones  may,  to  a  moderate  extent,  within  the  degree  producing 
cracks.  Cracks  in  Portland  cement  indicate  too  much  carbonate  of  lime, 
and  in  the  Vicat  cements  too  much  lime  in  the  original  mixture. 

NOTE. —  Your  committee  thinks  it  useful  to  insert  here  a  table  showing  the  average 
minimum  and  maximum  tensile  strength  per  square  inch  which  some  good  cements  have 


AMERICAN    CEMENTS.  Ill 

attained  when  tested  under  the  conditions  specified  elsewhere  in  this  report.    Within  the 
limits  given  in  the  following  table,  the  value  of  a  cement  varies  closely  with  the  tensile 
strength  when  tested  with  the  full  dose  of  sand. 
American  natural  cement,  neat :  — 

i  day,  i  hour  or  until  set  in  air,  the  rest  of  the  24  hours  in  water,  from  40  Ibs.  to  80  Ibs. 

i  week,  i  day  in  air,  6  days  in  water,  from  60  Ibs.  to  100  Ibs. 

i  month  (2  S  days),  i  day  in  air,  27  days  in  water,  from  100  Ibs.  to  150  Ibs. 

i  year,  i  day  in  air,  the  remainder  in  water,  from  300  Ibs.  to  400  Ibs. 

American  and  foreign  Portland  cements,  neat :  — 

i  day,  i  hour,  or  until  set,  in  air,  the  rest  of  the  24  hours  in  water,  from  100  Ibs.  to 
140  Ibs. 

i  week,  i  day  in  air,  6  days  in  water,  from  250  Ibs.  to  550  Ibs. 

i  month  (28  days),  i  day  in  air,  27  days  in  water,  from  350  Ibs.  to  700  Ibs. 

i  year,  i  day  in  air,  the  remainder  in  water,  from  450  Ibs.  to  800  Ibs. 

American  natural  cement,  i  part  of  cement  to  i  part  of  sand  :  — 

i  week,  i  day  in  air,  6  days  in  water,  from  30  Ibs.  to  50  Ibs. 

i  month  (28  days),  i  day  in  air,  27  days  in  water,  from  50  Ibs.  to  80  Ibs. 

i  year,  i  day  in  air,  the  remainder  in  water,  from  200  Ibs.  to  300  Ibs. 

American  and  foreign  Portland  cements,  i  part  of  cement  to  3  parts  of  sand  :  — 

i  week,  i  day  in  air,  6  days  in  water,  from  80  Ibs.  to  125  Ibs. 

i  month  (28  days),  i  day  in  air,  27  days  in  water,  from  100  Ibs.  to  200  Ibs. 

i  year,  i  day  in  air,  the  remainder  in  water,  from  200  Ibs.  to  350  Ibs. 

Standards  of  minimum  fineness  and  tensile  strength  for  Portland  cement,  as  given  below, 
have  been  adopted  in  some  foreign  countries. 

In  Germany,  by  Berlin  Society  of  Architects,  Society  of  Manufacturers  of  Bricks,  Lime, 
and  Cement,  Society  of  Contractors,  and  Society  of  German  Cement  Makers. 

STANDARD  OF  1877. 

Fineness,  not  more  than  25  per  cent,  to  be  left  on  sieve  of  5,806  meshes  per  square  inch. 
Tensile  strength,  i  part  cement,  3  parts  sand,  i  day  in  air,  27  days  in  water,  113.78  Ibs. 
per  square  inch. 

STANDARD   OF    1878. 

Fineness,  not  more  than  20  per  cent,  to  be  left  on  sieve,  as  above. 

Tensile  strength,  same  mixture  and  time  as  above,  142.23  Ibs.  per  square  inch. 

In  Austria,  by  Austrian  Association  of  Engineers  and  Architects. 

STANDARD   OF    1878. 

Fineness,  same  as  German  of  1878. 

Tensile  strength,  same  mixture  as  above,  7  days,  i  day  in  air,  6  days  in  water,  113.78  Ibs. 
per  square  inch. 

28  days,  i  day  in  air,  27  days  in  water,  170.68  Ibs.  per  square  inch. 

In  Austria  a  standard  for  the  minimum  fineness  and  tensile  strength  of  Roman  cement 
was  established  and  generally  accepted,  as  follows  :  — 

STANDARD   OF    1878. 

Fineness,  same  as  Portland. 

Tensile  strength  (i  part  of  cement,  3  parts  of  sand),  for 
Quick  setting  cement  (taking  15  minutes  or  less  to  set) :  — 
7  days,  i  day  in  air,  6  days  in  water,  23  Ibs.  per  square  inch. 
28  days,  i  day  in  air,  27  days  in  water,  56.9  Ibs.  per  square  inch. 
Slow  setting  cement  (taking  more  than  15  minutes  to  set) :  — 
7  days,  i  day  in  air,  6  days  in  water,  42.6  Ibs.  per  square  inch. 


112  AMERICAN   CEMENTS. 

28  days,  i  day  in  air,  27  days  in  water,  85.3  Ibs.  per  square  inch. 

The  Roman  cements  correspond  to  those  classified  in  this  report  under  the  head  of 
natural  cements. 

Standards  have  been  adopted  also  in  Sweden  and  Russia. 

SAMPLING. 

There  is  no  uniformity  of  practise  among  engineers  as  to  the  sampling 
of  the  cement  to  be  tested,  some  testing  every  tenth  barrel,  others  every 
fifth,  and  others  still  every  barrel  delivered.  Usually,  where  cement  has  a 
good  reputation,  and  is  used  in  large  masses,  such  as  concrete  in  heavy 
foundations,  or  in  the  backing  or  hearting  of  thick  walls,  the  testing  of 
every  fifth  barrel  seems  to  be  sufficient ;  but  in  very  important  work,  where 
the  strength  of  each  barrel  may  in  a  great  measure  determine  the  strength 
of  that  portion  of  the  work  where  it  is  used,  or  in  the  thin  walls  of  sewers, 
etc.,  etc.,  every  barrel  should  be  tested,  one  briquette  being  made  from  it. 

In  selecting  cement  for  experimental  purposes,  take  the  samples  from 
the  interior  of  the  original  packages,  at  sufficient  depth  to  insure  a  fair 
exponent  of  the  quality,  and  store  the  same  in  tightly  closed  receptacles  im- 
pervious to  light  or  dampness  until  required  for  manipulation,  when  each 
sample  of  cement  should  be  so  thoroughly  mixed,  by  sifting  or  otherwise, 
that  it  shall  be  uniform  in  character  throughout  its  mass. 


For  ascertaining  the  fineness  of  cement  it  will  be  convenient  to  use 
three  sieves,  viz. :  — 

No.  50  (2,500  meshes  to  the  square  inch),  wire  to  be  of  No.  35  Stubb's 
wire  gauge. 

No.  74  (5,476  meshes  to  the  square  inch),  wire  to  be  of  No.  37  Stubb's 
wire  gauge. 

No.  100  (10,000  meshes  to  the  square  inch),  wire  to  be  of  No.  40 
Stubb's  wire  gauge. 

The  object  is  to  determine  by  weight  the  percentage  of  each  sample 
that  is  rejected  by  these  sieves,  with  a  view  not  only  of  furnishing  the 
means  of  comparison  between  tests  made  of  different  cements  by  different 
observers,  but  indicating  to  the  manufacturer  the  capacity  of  his  cement 
for  improvement  in  a  direction  always  and  easily  within  his  reach.  As 
already  suggested  in  another  connection,  the  tests  for  tensile  strength 
should  be  applied  to  the  cement  as  offered  in  the  market,  as  well  as  to 
that  portion  of  it  which  passes  the  No.  100  sieve. 

For  sand,  two  sieves  are  recommended,  viz. :  — 

No.  20  (400  meshes  to  the  square  inch),  wire  to  be  of  No.  28  Stubb's 
wire  gauge. 


AMERICAN    CEMENTS.  113 

No.  30  (900  meshes  to  the  square  inch),  wire  to  be  of  No.  31  Stubb's 
wire  gauge. 

These  sieves  can  be  furnished  in  sets  as  follows,  an  arrangement  hav- 
ing been  made  with  a  manufacturer  of  such  articles,  by  which  he  agrees 
to  furnish  them  of  the  best  quality  of  brass  wire  cloth,  set  in  metal  frames, 
the  cloth  to  be  as  true  to  count  as  it  is  possible  to  make  it,  and  the  wire 
to  be  of  the  required  gauge.  Each  set  will  be  enclosed  in  a  box,  the 
sieves  being  nested. 

Set  A,  three  cement  sieves,  to  cost  $4.80. 

No.  100 7    ins.  diameter. 

No.    74 6^  „         „ 

No.    50 6       „        „ 

Set  B,  two  sand  sieves,  to  cost  $4. 

No.    30 8    ins.  diameter. 

No.    20 7^  „         „ 

STANDARD    SAND. 

The  question  of  a  standard  sand  seems  one  of  great  importance,  for 
it  has  been  found  that  sands  looking  alike  and  sifted  through  the  same 
sieves  give  results  varying  within  rather  wide  limits. 

The  material  that  seems  likely  to  give  the  best  results  is  the  crushed 
quartz  used  in  the  manufacture  of  sandpaper.  It  is  a  commercial  product, 
made  in  large  quantities  and  of  standard  grades,  and  can  be  furnished  of 
a  fairly  uniform  quality.  It  is  clean  and  sharp,  and  although  the  present 
price  is  somewhat  excessive  (3  cents  per  pound),  it  is  believed  that  it  can 
be  furnished  in  quantity  for  about  $5  per  barrel  of  300  Ibs.  As  it  would  be 
used  for  test  only,  for  purposes  of  comparison  with  the  local  sands,  and 
with  tests  of  different  cements,  not  much  of  it  wTould  be  required.  The 
price  of  the  German  standard  sand  is  about  $1.25  per  112  Ibs.,  but  the 
article  being  washed  river  sand  is  probably  inferior  to  crushed  quartz. 
Crushed  granite  could  be  furnished  at  a  somewhat  less  rate  than  quartz, 
and  crushed  trap  for  about  the  same  as  granite,  but  no  satisfactory  estimate 
has  been  obtained  for  either  of  these. 

The  use  of  crushed  quartz  is  recommended  by  your  committee,  the 
degree  of  fineness  to  be  such  that  it  will  all  pass  a  No.  20  sieve  and  be 
caught  on  a  No.  30  sieve.  Of  the  regular  grade,  from  1 5  to  37  per  cent, 
of  crushed  quartz  No.  3  passes  a  No.  30  sieve,  and  none  of  it  passes  a 
No.  50  sieve.  As  at  present  furnished,  it  would  need  resifting  to  bring  it 
to  the  standard  size,  but  if  there  were  sufficient  demand  to  warrant  it,  it 


114  AMERICAN   CEMENTS. 

could  undoubtedly  be  furnished  of  the  size  of  grain  required  at  little,  if 
any,  extra  expense. 

A  bed  of  uniform,  clean  sand  of  the  proper  size  of  grain  has  not  been 
found,  and  it  is  believed  that  to  wash,  dry,  and  sift  any  of  the  available 
sands  would  so  greatly  increase  its  cost  that  the  product  would  not  be 
much  cheaper  than  the  crushed  quartz,  and  would  be  much  inferior  to  it 
in  sharpness  and  uniform  hardness  of  particles. 

MOLDS. 

The  molds  furnished  are  usually  of  iron  or  brass,  the  price  of  the 
former  being  $2,  and  of  the  latter  $3  each.  Wooden  molds,  if  well  oiled 
to  prevent  their  absorbing  water,  answer  a  good  purpose  for  temporary 
use,  but  speedily  become  unfit  for  accurate  work.  A  cheap,  durable, 
accurate,  and  non-corrodible  mold  is  much  to  be  desired,  but  is  not  yet 
upon  the  market.  Plates  Nos.  XLIV.  and  XLV.  show  the  form  of  bri- 
quette and  of  metal  mold  recommended.  It  may  be  added  that  your  com- 
mittee are  not  in  entire  accord  with  respect  to  the  merits  of  this  form  of 
briquette,  its  principal  defect  being  that  the  rupture  must  take  place  at  the 
neck  or  smallest  section,  whether  the  strain  be  one  of  extension  only  or 
otherwise.  With  a  briquette  of  such  form  that  oblique  strains  would 
usually  produce  rupture  in  oblique  directions,  the  trials  taking  this  charac- 
ter would  be  rejected,  and  the  accuracy  of  the  results  correspondingly 
increased  thereby. 

CLIPS. 

In  using  the  clips  recommended  in  the  preliminary  report,  it  was 
found  in  some  instances  that  the  specimens  were  broken  at  one  of  the 
points  where  they  were  held.  This  was  undoubtedly  caused  by  the  in- 
sufficient surface  of  the  clip,  which,  forming  a  blunt  point,  forced  out  the 
material.  Where  the  specimens  were  sufficiently  soft  to  allow  this  point 
to  be  imbedded,  they  broke  at  the  smallest  section,  but  when  hard  enough 
to  resist  such  imbedding  they  showed  a  wedge-shaped  fracture  at  the  clips 
To  remedy  this  the  point  should  be  slightly  flattened  so  as  to  allow  of 
more  metal  surface  in  contact  with  the  briquette.  Clips  made  in  this  way 
have  been  used,  and  good  results  obtained. 

To  adapt  the  I  in.  clips  of  the  Riehle  machine  only  a  slight  amount 
of  work  is  necessary;  the  ends  being  rounded,  as  shown  in  Plate  No. 
XLVL,  will  admit  the  proposed  new  form  of  briquette,  and  yet  not 
prevent  the  use  of  the  old  one,  thus  allowing  comparative  tests  of  the  two 
forms  to  be  made  without  changing  the  clips. 

There  should  be  a  strengthening  rib  upon  the  outside  of  the  clips,  as 


AMERICAN   CEMENTS.  115 

shown  in  Plate  No.  XLVL,  to  prevent  them  from  bending  or  breaking 
when  the  specimens  are  very  strong. 

The  clips  should  be  hung  on  pivots,  so  as  to  avoid,  as  much  as  pos- 
sible, cross  strain  upon  the  briquettes. 

MACHINES. 

No  special  machine  has  been  recommended,  as  those  in  common  use 
are  of  good  form  for  accurate  work,  if  properly  used,  though  in  some 
cases  they  are  needlessly  strong  and  expensive.  Machines  with  spring 
balances  are  to  be  avoided,  as  more  liable  to  error  than  others. 

It  is  by  no  means  certain  that  there  exists  any  great  difference  in  well- 
made  machines  of  the  standard  forms  given. 

The  experiments  of  the  committee  do  not  seem  to  justify  an  expres- 
sion of  preference  for  any  one  machine.  Plates  Nos.  XLVII.  and  XLVIII. 
show  three  American  machines,  with  the  prices  obtained  from  the  manu- 
facturers. 

AMOUNT    OF    MATERIAL. 

The   amount  of   material  needed  for   making  five  briquettes  of   the 
standard  size  recommended  is,  for  the  neat  cements,  about  i%  Ibs.,  and 
for  those  with  sand,  in  the  proportion  of  3  parts  of  sand  to  i  of  cement, 
about  iX  Ibs.  of  sand,  and  6%  ozs.  of  cement. 
All  of  which  is  respectively  submitted. 

Q.  A.  GILLMORE, 

Chairman. 

D.  J.  WHITTEMORE. 
J.  HERBERT  SHEDD. 
ELIOT  C.  CLARKE. 
ALFRED  NOBLE. 
F.  O.  NORTON. 
W.  W.  MACLAY. 
LEONARD  F.  BECKWITH. 
THOS.  C.  McCoLLOM. 

In  February,  1895,  Cecil  B.  Smith,  Ma.  E.,  M.,  Can.  Soc.  C.  E. 
Assistant  Professor  of  Civil  Engineering,  McGill  University,  Mon- 
treal, delivered  before  the  Canadian  Society  of  Civil  Engineers  the 
following  exhaustive  dissertation  on  the  TESTING  OF  CEMENTS, 
which,  through  his  courtesy  and  the  courtesy  of  the  society  named, 
we  are  permitted  to  publish  in  full :  — 


116 


AMERICAN    CEMENTS. 


?2 

&6S> 

1 1 


.    • 

slilsl 


i!i 
i! 

o-S 


.^  is.S 


Isll 


.ls 


isfl 

g^! 

I  =  •££ 

C/2  rt^  - 

o  ss'S 


S  cj" 

rf 


. 

M 


111  s 


ill 


ues 
ess. 


c  o>  co 

111 

ot/5 
ScS 

«  0     . 
MiJfeO 


n  80  siev 
on  100  ,, 
on  150  ,, 
on  180  ,, 
mesh. 


2,,0-ss 
- 


•o 

II 

££ 


5-S      6  ^-d  «« 

VO      N      M 


£  | 


N          10-3    i. 


M 


a 


, 


o      ^-J 

fls 


. 

9M     SB  t*  *"  5 

<  Js  t  M<»  g  a 


•gl 


AMERICAN    CEMENTS. 


117 


s!l 


•SJS-S 


«J-**a  9 


•S  *  £ 

CO  -    - 


—;   O  (X>   0 


S  S, 


peci 


3  8 

&  tC 


w 
m 


o  •» 
T.8  . 


J"     ^ 
! 


118 


AMERICAN    CEMENTS. 


ground  « 

*  §|  § 

ll 

il5| 

Sl||j 

n 

^•all  L 

^             ^Q   c 

III  1^ 

2s3            ^ 

H      «      ,0    fe^ 

to  rt  2  b/D      ' 

H 

llpi 

Time  of  Mixing. 

i  minute  for 
quick  setting,  2 
minutes  for  slow 
setting,  mechan- 
ical mixer. 

O  o 

'S 

-ll 

i  minute  o  r 
more,  hand  or  me- 
chanical mixing. 

1*1  i 

ill 

5  minutes  by 
hand  on  a  slab, 
temperature  of  air 
59°  to  64°  F. 

No.  of  tests 
used  for 
Averages. 

If. 

S8 

-, 

Smallest 
section  only. 

o 

•P 

VO 

'3     § 

S2 

e 

03 

en 

w)  rtO 
^  o>  o\ 

M    if) 

rJ 

3 
O 

3 
O 

I 

1 

O  £3*0^ 

^'cfe0^ 

•H   £«' 

^ 

M 

Q 

I* 

^ 

"3'~.2 

J§S 

^Q  § 

J8« 

!z^ 

^J 

|1 

i's" 

K5 

7>2 

i 

4 

£ 

|| 

S  g  g.s 

Is 

1't^ 
2   'w 

•0  M«i 

8.J1 

E-Sj2 

ow  put  in  Mol 

S.S. 

X 

ll 

""  «S 

|lj 

C  3 

"""  O 

11! 

HL 

5-53  * 
"g  &- 

SjJi 

3  1=1 

W 

21 

iHii 

PH   fe  ^ 
O 

£l!§ 

•B 

«!l§ 

,C  OTs«  fl 

3  <^  fo 

O    . 

S 

^  o    • 

3 

—  rt       ^^ 

OJ  ^    ^ 

•a 

*  &S 

C         .  43 

-—       ^ 

c 

i 

ys^« 

2 

O 

°S  As 

U  S  B 

•3 

12  0  rt.2 

'a 

''B 

j-i^g 

U  2.0 

j 

T3  **   >   0 

'n  r^-"  £  • 

"S  .,  *.  • 

a 

rt  "^  * 

rt  -^  -?       <[j 

f2 

w 

OT  ^  M  O 

W  «  3  2  u 

.5 

0*°^ 

o<3  ft'53 

O-OM 

AMERICAN    CEMENTS.  119 

CEMENT  TESTING. 

This  subject  has  so  often  been  written  on,  and  is  being  so  con- 
tinually and  persistently  investigated,  that  it  forms,  as  it  were,  an 
inexhaustible  mine. 

But  this  very  feature  shows  how  very  important  and  yet  how 
little  understood  it  is,  for  when  investigators  continue  to  disagree, 
the  presumption  is,  that  there  is  either  a  lack  of  agreement  as  to  the 
basis  on  which  the  investigations  are  made,  or  else  a  failure,  up  to 
the  present,  to  solve  all  the  intricate  mazes  of  the  problem,  or  indeed 
a  combination  of  the  two. 

To  illustrate  the  first  point,  a  tabular  synopsis  (Table  I.)  is  pre- 
sented, giving  the  present  standard  tests  in  use,  in  various  countries, 
according  to  the  latest  obtainable  information.  The  variations,  in 
many  cases,  are  too  great  to  be  reconciled,  in  others  trifling ;  but  it 
is  evidently  difficult  to  compare  results  obtained  in  different  coun- 
tries, and  a  hopeless  task  to  ever  bring  them  to  a  uniform  standard. 
What  it  behooves  us,  as  Canadian  engineers,  to  do  is  to  take  such 
sensible  and  immediate  action  on  the  subject  as  will  commend  itself 
to  the  good  graces  of  all  of  us,  if  possible,  or,  if  not,  of  a  great 
majority  of  those  who  test  the  manufactured  article. 

However,  before  proposing  a  mode  of  conducting  such  tests  as 
will  (according  to  the  author's  experience)  be  of  practical  utility  to 
practical  men,  the  following  Table  (Table  II.)  is  presented  to  the 
society  as  embodying  results  which  have  been  obtained  during  the 
last  two  sessions,  in  making  ordinary  commercial,  private,  and  student 
tests  (chiefly  commercial  and  private). 

Many  results  have  been  discarded  as  being  inaccurate,  and  only 
those  are  recorded  here  which  are  believed  to  be  very  close  to  the 
truth,  much  closer  than  is  ordinarily  obtained. 

These  results  have  been  classified  according  to  country  of 
manufacture,  and  somewhat  on  a  scale  of  increasing  tensile  strength. 

Let  us  consider  the  various  qualities  given  in  their  tabular 
order. 

(a)  Specific  Gravity. 

The  average  of  Canadian  Portlands  =  3.11. 

The  average  of  English  Portlands  =  3.10. 

The  average  of  Belgian  Portlands  =  3.055. 

The  average  of  all  Portlands  (16)  =  3.09. 


120 


AMERICAN    CEMENTS. 


TABLE  II. 

CONDENSED  TABLE  OF  CEMENT  TESTS.  1893-1894. 

lAverage  Tensile  Strength  in  pounds  per  square  inch. 

O 

1 

-  >.  1     :::::::::  | 

fOOO  \O    ro 

T| 

;|i  ;;:;;; 

•  00      

"ii*:  ill: 

:  :  :  :  : 

:  :  :  : 

«i 

:  :  : 

Nl 

N    ^     

::::"»::::: 

•£ 

(to^JCSiN.  - 

-  OO   ro  •*   •*  t^  N   ir,  r>  o 

oo1-"3  c^  o-  1? 

:    %Z 

*>         **                     >«•  T    f  TT 

IN 

-| 

:::::::::  :| 

:$: 

MJ3 

£ 

;;;;;:;;; 

:  :  :  SSJ  :  :  ?S  : 

:  S, 

-1 

^?ffMsll 

8>  -  S  ^  £3  $£•  5  8s 

2  a  g:.g  ^ 

:     J?.S 

00 

*S.  o  I?  SCS.<?)  28^ 

'vS  oS,^?^  :  :  ol  ££N  R3» 

roNPONfn                   -|            N    f>  f)    Tt- 

Time  of  setting 
in  air. 

1 

^V8V2V8V8"S,     : 

iVsVsVsVs^ 

X§o8» 

ii 

k««%>^ 

|| 

>>ii> 

o  >n  oV.vbvovo 

O^OroOfoO           • 

O    O    O    O    O    O    O 

•*•  o  ">  O  "-1  •*  N        ; 

•    O   "5  "1  O     ••  O    0    r^  ~ 

w 

plllb 

1111111  111 

bfi  W>  M>  60  W>  bfl       b       E 
4)          O 

>•       * 

"O 

a 

: 

§s 
1 

IS 

f  ^  ".  T°9 

-s^ffffSii 

2^8  8  ^^ 

l« 

-^---t^O'J 

irn^s^n 

•*  •*  ooo  N 

•  oo 

:  o 

N    N                                          N 

IS 

;  o. 

-  «                      o 

|S 

ooooooooo    oooooooooo 

00000 

i°  : 

Per  cent,  wat- 
er for  standard 
consistency. 

ii^frSTiii***'.') 

r2«?N«?C?NNNWN 

f>  N    N    N    N 

m  10   • 

Specific 
Gravity. 

o^22g-2  :  :  : 

•    OOOOO    -    <->rON    "• 

f^  ro  N    OOO 

O  O    O    O   O 

;    i   9 

to  N    fO  fO  M  M    .      .      . 

.    wMfOfOrororofO^ 

N   rotowrr 

Obtained 
from. 

Illllllll 

QO^QQQQOQQ 

ji>  jy  Jj  Jy  c 

1  ':  ': 

No.  in  Table. 

ti  *<i     Vj 

l^oooo^^n 

^>o  t-oo  o> 

O  «  «  <r> 

1    N     N    N    N 

'f  o 

ccccdcccc 

•l^-i-l-i^^^^^ 

550,0,0^0, 

c  c  c  c  c 
!&jiJifSif5 

3 

AMERICAN    CEMENTS. 


121 


ir.  N  O     • 
tv  O  N      • 


•  vO    10O      •••NO 

.    „  „    ^    .      .      .    0    0> 


iilMm 


122 


AMERICAN    CEMENTS. 


||  Transverse  Strength.  ||  No.  of  Tests. 

Trans. 

0000«NOOO 

Nu^OONOOOOO 

0   0   0    0   O 

N    N    N    «           O 

Com  p. 

-00.0*^0  oo 

r          °° 

3tol.  Neat  l"xl"  broken  on  6"  centers.  H 

1  n 

asile. 

00 

1 

;  1*5.  sjM 

•    •  o  o  

ijjjjjjjjj 
LUlLLLLll 

10  "•  :::::::: 
:  :  :  :  8  :  :  :  :  • 

...     -00 

N    t>.  rOO          ^ 

?  ijf  ; 

i 

2 

r: 

p 

? 
1 

•= 

c 
= 

^ 

1 

£ 

* 

> 

u 
< 

2 

M 

3 

1 
1 

—  -^ 

«• 

&  ::::::: 

liiiiiM 

J.    .    .    .  in   .     . 

•  •  •  •  00  

:  .  :  :  8  :  -  :  :  : 

r*>X>   O     • 

co| 

jf  :;:.}::  :'j 

8  s,  :  ;;:;:; 

1:  Ml 

*    •  ef  ^- 

:  2  :  : 

-ti 

>iri"  *«tr>*  *  * 

UiM!:!:: 

&  :  :  :  8. 

jiij 

ilfl 

.  .    *>  .  .  . 

AMERICAN    CEMENTS.  123 

It  would  seem  advisable,  therefore,  to  specify  a  minimum  for 
Portlands  of  3.10. 

The  samples  were  not  dried  or  prepared  in  any  way ;  if  they 
were  dried  for  fifteen  minutes,  according  to  English  practise,  it  is 
probable  they  would  go  somewhat  higher. 

It  will  be  noticed  that  the  only  two  Portlands  (  ? )  whose  specific 
gravities  were  low  (Belgians  Nos.  16  and  1 7)  were  both  poor  cements. 
One,  No.  16,  sets  slowly,  and  the  briquettes  made  for  4  week  tests, 
and  immersed  in  water  after  24  hours  were  found  sloughed  down  in 
the  tanks,  and  had  evidently  run  and  set  over  again !  They  would 
not  give  any  test  to  speak  of.  Evidently  the  hydraulic  property,  in 
24  hours,  was  not  enough  to  hold  them  together,  while  the  other  one 
(No.  17)  failed  in  the  blowing  test.  Altogether,  it  is  doubtful 
whether  these  cements  are  Portlands  or  naturals,  although  sold  as 
the  former,  owing  to  their  color  being  gray. 

It  will  be  noticed,  with  satisfaction,  that  Canadian  Portlands 
stand  at  the  top  in  specific  gravity,  judging  by  the  samples  tested, 
which  were,  however,  all  received  from  manufacturers. 

The  specific  gravity  of  natural  cements  might  be  placed  at  2.95, 
although  it  is  not  so  likely  to  be  under-run,  owing  to  the  ease  with 
which  this  can  be  obtained. 

(fr)   Water  required  for  standard  consistency. 

This  is  considered  by  many  to  be  very  important ;  but  many 
tests  have  demonstrated  to  the  writer  that  what  is  especially  needed 
is  that  there  shall  be  sufficient  to  make  good  briquettes ;  to  err,  say, 
i  per  cent,  in  adding  water  is  fatal  if  too  little,  while  if  too  much,  it 
does  not  seem  to  affect  the  strength  of  briquettes  at  I  week,  certainly 
not  at  4  weeks.  This  is  contrary  to  statements  often  made  regarding 
the  increased  strength  given  by  a  minimum  amount  of  water ;  but 
probably  what  is  referred  to  is  an  excess  of  water  sufficient  to  make 
a  thin  batter  or  soup.  Undoubtedly,  such  an  amount  not  only  makes 
the  briquettes  shrink  and  crack  in  drying,  but  will  seriously  affect 
the  early  strength. 

A  very  peculiar  effect  was  met  with  in  two  Canadian  and  one 
English  Portlands.  They  were  evidently  fresh,  and  when  mixed 
with  a  normal  amount  of  water  would  work  into  a  good  plastic  mass, 
but  in  about  one  or  two  minutes  after  the  water  was  added,  they 
would  suddenly  set  so  hard  that  it  was  useless  to  attempt  to  put 
them  in  the  molds. 


124  AMERICAN    CEMENTS. 

By  increasing  the  per  cent,  of  water  to  about  thirty,  a  thin  batter 
was  made,  which  could  be  got  into  the  molds  before  this  action  took 
place ;  of  course  this  amount  of  water  made  the  set  very  slow,  and 
deadened  the  indurating  action  in  I  week  tests. 

When  tests  were  made,  several  weeks  later,  on  these  cements, 
this  effect  had  disappeared  ;  perhaps  some  one  connected  with  the 
industry  can  explain  the  cause  of  this  action. 

(c)     Residues  or  Fineness. 

The  variation  is  enormous,  as  the  following  statement  shows :  — 


Residue  on  No.  50  Sieve. 
Per  Cent. 

Residue  on  No.  80  Sieve. 
Per  Cent. 

Residue  on  No.  120  Sieve 
Per  Cent. 

Coarsest              31.4 
Finest                  0.25 

52.2 
2.7 

61.2 
6.7 

The  English  Portlands  are  generally  very  coarse,  as  will  be 
seen,  and  the  selected  Canadian  ones  fine. 

It  is  not  putting  it  too  severely  to  say  that  specifying  a  certain 
residue  on  No.  50  sieve  is  a  direct  premium  on  coarse  grinding  and 
so,  in  fact,  are  neat  tensile  tests. 

For  instance,  English  brands,  Nos.  10,  11,  12,  13,  and  Nos. 
14  A,  14  B,  are  all  evidently  ground  to  pass  a  specification  of  5  per 
cent,  residue  on  No.  50  sieve,  and  are  all  very  coarse  when  sifted  on 
finer  ones,  thus  plainly  showing  the  failure  of  the  specification  to 
obtain  as  good  a  product  as  possible. 

The  author  would  urge  the  severest  requirements  for  fineness. 

Various  papers  read  and  the  statements  of  manufacturers  them- 
selves go  to  show  that  the  increased  cost  is  very  slight,  not  more 
than  ten  cents  per  barrel  between  ordinary  and  fine  grinding, 

10  per  cent,  residue  on  No.  80  sieve  ) 

.j  x,  .        has  maximums  are  not  too 

20  per  cent,  residue  on  No.  120  sieve  > 

high  for  present  facilities  for  fine  grinding ;  this  would  let  in  three 
out  of  four  Canadian  Portlands  tested,  one  out  of  ten  English  Port- 
lands tested,  two  out  of  four  Belgian  Portlands  tested,  or  in  all  six 
out  of  eighteen  brands.  There  are  signs,  however,  that  the  English 
manufacturers  are  waking  up  to  finer  grinding,  and  will  soon  fall 


AMERICAN    CEMENTS.  125 

into  line ;  there  is  no  reason  why  educating  influences  should  not 
bring  grinding  down  much  finer  still  for  ordinary  brands,  but  for  the 
present,  too  much  severity  would  defeat  the  object  in  view.  (For 
tests  on  the  effect  of  fine  grinding,  see  Series  I.  of  Experiments.) 

(*/)  The  time  of  incipient  and  final  set,  as  found  by  Gillmore's 
needles,  does  not  seem  to  affect  the  strength,  except  for  very  short 
tests,  when  the  slow  settings  are  generally  stronger.  Good  cements 
may  be  either  the  one  or  the  other ;  but  ordinarily,  unless  for  tidal 
work,  a  slow  setting  one  has  the  desirable  feature  of  allowing  masons 
to  mix  and  use  good-sized  batches  of  mortar,  without  constant  tem- 
pering, which  is  the  practise  with  quick-setting  ones,  much  to  their 
own  hurt. 

(e)  The  blowing  test  advised  by  Faija  has  detected  a  "  blowey  " 
tendency  in  several  instances  ;  but  much  late  evidence  seems  to  throw 
some  discredit  on  blowing  tests,  whether  made  with  hot  or  boiling 
water,  on  the  ground  that  manufacturers  can,  by  the  addition  of  sul- 
phate of  lime,  cause  the  cement  to  be  so  slow  setting  and  set  so 
strongly  as  to  resist  the  blowing  tendency  of  so  much  as  3  per 
cent,  of  free  lime  added  after  the  cement  had  been  burnt.  If  this  is 
a  fact,  chemical  analysis  will  need  to  be  resorted  to  more  frequently, 
to  detect  this  dangerous  adulteration,  which  is  fatal  in  sea-water  and 
bad  in  any  case,  as  the  great  strength  which  it  gives  to  cements  at 
early  dates  is  apt  to  decrease  at  longer  periods.  Belgian  No.  19 
cement  tested  gave  higher  results  at  I  week  than  at  4  weeks ;  this 
looks  a  little  suspicious. 

Cements  have  been  tested  usually  neat ;  the  Germans  have 
reached  the  stage  of  three  to  one  mixtures  as  the  deciding  test,  and 
this  would  seem  to  be  the  only  rational  way  of  testing  a  cement,  i.  e., 
in  the  same  condition  as  it  is  used. 

The  difficulty,  however  —  and  it  is  a  very  serious  one  —  has 
been  to  get  anything  like  uniform  results  in  sand  tests.  The  varia- 
tion in  putting  the  mortar  in  the  molds  has  been  so  much  more  than 
the  variation  in  the  cementing  value  of  the  cement  that  the  tests  were 
valueless,  so  that  most  testers  have  clung  to  neat  tests  as  being  simple 
and  a  fair  index  of  cementing  qualities.  That  this  view  is  in  fault 
and  misleading,  every  tester  will  admit,  and  it  is  only  partly  avoid- 
ing the  difficulty  to  specify  a  certain  fineness,  strength,  and  specific 
gravity  in  combination,  as  even  then  the  results  are  not  definite,  be- 


126  AMERICAN    CEMENTS. 

cause  each  cement  is  different  in  cementiecous  value.  However,  for 
those  who  have  facilities  for  testing  cement  neat  only,  —  and  these 
will  probably  be  in  the  majority  for  some  time  to  come, —  it  would 
seem  that  350  Ibs.  at  i  week  neat  and  450  Ibs.  at  4  weeks  neat  are 
easily  obtained,  and  quite  enough  to  specify.  Eleven  brands  tested 
would  give  this  much  strength  and  stand  the  blowing  test,  and  of 
these  there  are  six  brands  fine  enough  for  10  per  cent,  residue  on  80 
sieve  and  20  per  cent,  residue  on  1 20  sieve,  with  a  specific  gravity 
varying  from  308  to  313,  while  the  six  brands  which  are  not  strong 
enough  are  also  too  coarse. 

The  tests  on  natural  cements  are  not  extensive  enough  to  form 
a  good  basis,  but  it  would  seem  easy  to  get  100  Ibs.  neat  at  i  week 
and  200  Ibs.  neat  at  4  weeks,  and  a  fineness  the  same  as  for  Port- 
lands. 

The  tests  on  No.  2  natural  and  No.  1 1  Portland  were  carried  on 
for  6  months,  and  show  the  natural  to  be  gaining  on  the  Portland, 
although  each  has  evidently  nearly  reached  a  maximum.  This 
would  seem  to  bear  out  the  idea  which  many  people  yet  have, 
that,  in  time,  a  natural  cement,  not  being  so  brittle,  will  catch 
up  to  a  Portland.  Long  time  tests  are  very  much  needed  on  this 
subject. 

Natural  cements  being  underburnt  (usually)  have  very  much  less 
combining  power  with  sand  ;  the  one  to  one  natural  is  not  as  strong 
as  two  to  one  Portland,  according  to  tests  made  last  year  as  per 
Table  II.  in  which  the  mixtures  were  made  with  15  percent,  of 
water  for  one  to  one,  and  1 2  per  cent,  of  water  for  three  to  one 
mixtures,  the  mortars  being  lightly  tamped  into  the  mold  with  an 
iron  rammer ;  the  tests  made  this  year,  however,  by  means  of  a  uni- 
form pressure,  give  much  higher  results  for  one  to  one  naturals,  when 
20  per  cent,  of  water  is  used,  which  would  seem  to  be  nearer  to  the 
amount  used  in  practise,  making  a  soft  plastic  mortar.  (See  pres- 
sure tests. ) 

Natural  cement  has  many  uses.  It  is  being  passed  aside  in 
many  quarters.  Why  ?  because  if  immersed  in  water  for  i  week  or 
4  weeks,  it  will  give  low  tensile  tests.  That  terror  of  the  present 
day,  the  testing  machine,  condemns  it. 


UNIVERSITY 


AMERICAN    CEMENTS. 


127 


Now  there  are  many  occasions  where  it  would  not  be  wise  to 
use  anything  but  the  best  Portlands  —  such  as  laying  mortar  in 
extreme  frost,  or  where  great  immediate  strength  is  required,  or 
for  subaqueous  work  generally ;  but,  on  the  other  hand,  no  one  doubts 
the  durability  of  good  natural  cement.  Works  in  Europe  hundreds  of 
years  old,  and  all  the  work  done  in  the  United  States  and  Canada 
previous  to  thirty  years  ago,  are  built  with  such  mortars,  and  stand 
as  witnesses  of  their  lasting  qualities. 

Moreover,  tests  made  on  No.  I  natural  cement  (see  Series  III., 
frost  tests)  show  that  while  it 
cannot  be  immediately  exposed 
to  extreme  cold,  yet  when  it  is 
exposed,  after  it  has  set,  it  will 
resist  frost  thoroughly,  and  be- 
come stronger  than  if  immersed 
in  water  at  an  ordinary  tem- 
perature. There  are  thousands 
of  situations  where  natural  ce- 
ment mortar,  i  cement,  2.  sand, 
will  be  found  amply  strong  for 
the  purposes  required,  in  which 
case  it  will  be  found  cheaper 
than  Portland  mortar,  i  cement, 
3  sand.  Referring  ahead  to 
Series  III.  (frost),  it  will  be  seen 
that  if  mortars  are  tested  in 
open  air,  the  Portlands  are 
weaker  and  naturals  stronger 
than  if  the  briquettes  had  been 
under  water.  This  is  a  point  of 
much  importance,  because  if 
work  is  to  be  done  which  will 
not  usually  be  submerged,  as  in  damp  foundations,  abutments  on 
land,  culverts,  etc.,  then  tests  made  in  open  air  will  give  results  more 
favorable  to  naturals.  In  so  many  words  our  standard  tests  say: 
"  Let  us  test  all  hydraulic  cements  under  water ;  whether  the  mortar 
as  used  will  be  so  or  not,  we  will  be  on  the  safe  side."  ,This,  as  a 
generality,  is  doubtless  best ;  but  if  we  consider  what  a  large  propor- 


128 


AMERICAN   CEMENTS. 


S  £ 


4  week  tests,  1  air,  27  water. 

Product 
col.  3  x 
col.  6. 

vq  ^vq  q 

ro  oo  inoo 

I! 

vq  N  N 

ill 

Per  cent 
of  eva- 
poration. 

fill 

inoovOvO 

0     • 

5i?i? 

2  : 

| 

Weight 
after  two 
day  s'  eva- 
poration. 

^-  <4*  in  in 

«oo"S  N 

•*•  i 

oo  m  M- 

00    M    N 

be 

1 

when 
tested  ir 
ounces. 

^as>? 

££3^ 

9  : 

:        : 

4-  •*•  4- 

I        | 

a 

r 

1 

J! 

li 

££§s 

4«i 

^.  ; 

; 

«*r 

-  ; 

Low- 
est. 

£££8    |    WJSS    |    *: 

O*«  N   »A 

fr 

Hl» 

*ss? 

2  : 

s** 

• 

<o 
S 

.0' 
1 

! 

Product 
col.  3  x 
col.  6. 

•*  wvO   "I- 

•"    O  00    «»> 

fx  0    «    - 

t^in-  o 

O  >O   tx 

O  moo  t- 

*?§  = 

in  O   l^  ^ 

^1  °^: 

vo'SS   §" 

0^8^ 
\o-j-o 

— 

Per  cent, 
of  eva- 
poration. 

mi 

MOO  moo 

in  rpvO   PJ 

o  6  06  oo 

in>O  oo'  oo 

in  4-  -^ 

Weight 
after  two 
days'  eva- 
poration. 

HI: 

nn 

9^89? 

oo  oo  tv  in 

oS^ 

1 

tested  in 
ounces. 

•6,-s-s.s 

S£q  s; 

^r^s 

SStfS. 

m  0s  ro 

c 
1 

1* 

*N  vO    t^"ro 

9??s 

^N  mm 

^11=2 

*    . 

Low- 
est. 

"1*1 

^:g\2 

^«=§S 

*?=! 

y^r. 

1* 

S>o2>~ 

^n 

SJ-?f 

H»» 

0  2  I? 

i  s  • 

0   0   0   0 

O  0   O   0 

0000 

SSS8 

222 

*H 

.^Sof 

s?** 

^«  s  s 

?Vg  a 

r«s 

e 

3 

fi 

i 

o 

M 

o 

0 

0 

o 

1 

n 

0 

N 

in 

6 

in 

6 

1 

AMERICAN    CEMENTS. 


129 


Iri 

£* 

fe 

3 

1 

Product 
col.  3  x 
col.  6. 

^"cor? 

Mil! 

00     -    -   O*  O* 

O  tn\o  O  oo 

HIM 

Per  cent, 
of  eva- 
poration. 

9|f 

*--?'- 

5  "-  ?  ? 

?-?.??  8. 

Weight 
after  two 
days'  eva- 
poration. 

3  w'ip 

imi 

,  |B  f 

00    10  N    N    10 

3-co3-co'£r 

.,     e   . 
A  £'    *> 

*3f 

ss.^e.5 

^     tCvo'oO      ?. 

tvOOOO  00  00 

sasts 

P 

Jjo 

Lbs.  per  sq,  in. 

<*   =3 

%** 

^s^ 

?rsfS5 

to  O   co'Vob 
10  t-*\o   •*•  N 

Mnei 

Low- 

00    10  ^        1        OO    N    M    •«•  CO 

N       JO  0^  l^     ^» 

\O     O   O  OO     "^ 

^vffvS^r? 

5,5:-S,£S 

tc-'f 

R$3 

,1?8a 

S??2" 

Scg-S'&S 

*«*** 

1  week  tests,  1  air,  6  water. 

Product 
co  .  3  x 
.col.  6. 

~    I 

N          « 

v£3    •*  f   -    CO 

1J1    vO    PC  t^.     M 

00  O    P)    K  O 

06  r^>  4-  co  co 
°r  co^c^°r 

Percent, 
ot  eva- 
poration. 

4-         - 

£s™~ 

N      -^-OO  sO       O 

N     in  t^s  q    OO 

8\g^S2- 

=2^^ 

Weight 
after  two 
days'  eva- 
poration. 

t^       00 

eo       •*• 

<SS"S!?? 

m    O    O  t^  00 

^2?^^ 

w  00    "*-00    »0 

to 

a   . 

sC* 

v?      «? 

P;?S^« 

\O     m      \O     O 

8.^RS8, 

s^jsas 

Lbs.  per  sq.  in. 

|l 

««•»! 

ffS-ffJ  2 

"S?f  J?"r? 

CO  CO   CO  CO  f? 

*t»5  tv  10*O*  « 
CO  N    CO  N    CO 

Low- 

os«oo 

2"00    0    N  00 

CO     O    «0  N      N 

O    N    N    t^  10 

t>\O     M     CO  t^ 
N    •*    CO  N    N 

£  * 

r?      •< 

SS?^:: 

t^     CO  O-  10     t^ 

snsa 

-    (N.NVO    CO 

Pressure 
per 

f! 

SSS 

22222 

00000 

22222 

O   O   O   O   O 

*M 

^ 

^o^ 

iK   ^ 

SN          v^ 

^JN          ^« 

-    -    N 

E 

3 

'S 

i 

2 

0 

0 

0 

0 

CO 

1 

6 

0 

6 

* 

0 

o 

0 

6 

130  AMERICAN    CEMENTS. 

tion  of  cement  is  used  in  situations  usually  not  submerged,  it  would 
seem  more  rational  to  test  cements  under  conditions  similar  to  those 
under  which  they  are  to  be  used  in  each  case,  be  it  in  water  or  air. 

As  before  mentioned,  all  the  sand  tests  given  in  the  Table 
(Table  II.)  were  made  by  tamping  the  mortar  lightly  into  the  molds 
with  an  iron  rammer  weighing  about  ^  Ib.  and  y2  in.  square  section. 

This  has  been  done  in  as  nearly  a  uniform  manner  as  possible. 
About  three  layers  were  tamped,  and  then  a  fourth  layer  smoothed 
off  with  a  spatula.  Every  effort  was  directed  toward  uniformity  in 
method,  and,  doubtless,  some  degree  of  accuracy  was  obtained ;  but 
it  was  felt  that  the  best  possible  would  only  enable  comparisons  to 
be  made  in  this  laboratory,  it  would  not  enable  any  to  be  made  with 
results  obtained  elsewhere. 

The  Cement  Committee  of  the  Society  (of  which  the  writer  was 
made  a  member,  by  invitation)  advised  that  tests  should  be  made 
under  a  pressure  of  10  Ibs.  per  square  inch.  It  was  not  defined  at  the 
time  whether  this  applied  to  sand  tests  only  or  to  neat  tests  also; 
but  the  necessity  for  pressure  is  not  so  great  in  neat  tests,  because 
any  one  with  ordinary  skill  and  practise  can  make  a  good  neat 
briquette,  and  a  light  pressure  will  not  affect  the  result  much,  as 
will  be  shown  farther  on. 

In  November  last  the  molds  for  applying  pressure  (see  drawings), 
which  were  from  a  design  of  the  writer's,  modified  by  Mr.  Withy- 
combe,  were  completed,  and  since  then  several  hundred  briquettes 
have  been  made  with  them.  It  would  seem  a  simple  matter  to  mix 
up  mortar,  put  it  under  a  plunger,  and  by  putting  on  10  Ibs.  per 
square  inch,  make  briquettes;  but  theory  and  practise  must  be 
fellow-laborers.  Now,  1 2  per  cent,  of  water  is  considered  the  correct 
thing  in  3  to  I  mixtures,  but  with  this  amount,  the  mortar  would 
not  pack  at  all  in  a  closed  mold  under  so  light  a  dead  pressure,  and 
it  is  light  dead  pressure  that  is  wanted ;  even  20  Ibs.  per  square  inch 
was  of  no  greater  effect ;  then  1 5  per  cent,  of  water  was  tried,  with 
very  little  better  results. 

It  was  finally  concluded  to  try  several  series  with  different  per- 
centages of  water,  and  thereby  determine  the  best  per  cent,  for  mak- 
ing a  good  briquette. 

These  series  (see  Table  III.)  ran  from  15  per  cent,  to  25  per 
cent,  of  water,  and  were  for  10  Ibs.  and  20  Ibs.  pressure  per  square 


AMERICAN    CEMENTS. 


131 


TABLE  IV. 

CONDENSED  SUMMARY  OF  PRESSURE  SAND  TESTS. 

Put  in  molds  with  20%  water,  20  Ibs.  per  square  inch. 

REMARKS. 

^7T    C^^TT 

ooooooooooooooooo 
rt"~     "     s     ~       r     "    :   ^  r  ^  z   ' 

H 

i 

1 
« 

3 

Product 
col.  3  x 
col.  6. 

Per  cent, 
of 
evaporation. 

?j     6  1  *   ?  Hf;?!! 

: 

Weight  after 
two  days' 
evaporation. 

1"    j  »  1  1  TJ?  ijii 

Weight 
when 
tested. 

11  *  3  1  5 

r 

t 

Average. 

§|     X  »  S    S  881SS^ 

Lowest. 

oO  ^          HI     ro    0        m,   r^  ^oo  O  «  PO  N 

Highest. 

N  t^        oo     N     <r>       •«•    inoo  oo  m  OxO  vO 

1  week  tests,  J  air,  6  water. 

Product 
col.  3  x 
col.  6. 

f^g"^     nTn??^       SJ-         2"J?o  WM 

Per  cent, 
of 
evaporation. 

"v?°     tC   "8    'S.      "Sv         S.'&vSoo'In 

-?CTOO:22     S       ffSJ^S0* 

Weight  after 
two  days' 
evaporation. 

U?-°^  <8  Lr  ?    S1     s^g1^^ 

Ttinm    -*     ^    ^-       ^-         ^.^^.,0^. 

Weight 
when 
tested. 

ls!!2S  3  2i:5!! 

Lbs.  per  sq.  in. 

Average. 

^Ztlcf  IT  J2  ^"    S?  ^23  ^flF*  2  S* 

Lowest. 

vOO^foooo     in       M     mrjOoOTj-  inoo 
•»  O^  -                     N        fON^comt^i-i 

Highest. 

RS»  rr  ff  t   ",  sf  ataff? 

Mixture. 

222  222     2  2222222 

Brand. 

V»?  "-*    2  «-»*?*  sr 

ooo    o    o    o      o    ooooooo 

132  AMERICAN   CEMENTS. 

inch  for  i  week  and  4  weeks,  and  each  result  tabulated  is  the  average 
of  5  briquettes,  and  the  whole  table  the  result  of  77  experiments,  or 
385  briquettes. 

The  result,  to  the  author's  mind,  is  definite ;  20  per  cent,  of  water 
is  just  sufficient  to  make  a  plastic  mortar,  so  that  a  good  briquette 
can  be  formed  while  more  water  tends  to  drown  the  cement,  and 
make  it  weaker  at  both  the  I  week  and  4  week  tests,  although  longer 
tests  would  probably  show  a  recovery  in  this  respect. 

This  20  per  cent,  applies  to  i  to  i  and  3  to  i  mixtures,  and  will 
probably  be  about  right  for  2  to  i  also,  if  it  is  desired  to  make  such 
tests.  It  is  conclusive  from  the  table  that  if  any  standard  test  under 
light  pressure  is  to  be  adopted  for  sand  tests,  20  per  cent,  of  water 
must  be  prescribed  as  a  definite  part  of  the  test,  and  in  this  way 
perfect  uniformity  obtained.  It  is  understood  that  the  sand  used  is 
standard  sand  dry  and  sharp,  a  finer  or  rounder  sand  would  allow 
less  water  to  be  used.  This  amount  of  water,  while  greater  than 
that  usually  given  by  authorities  whose  method  of  making  sand 
briquettes  is  by  some  severe  hammering  process  (e.  g.,  German)  is  still 
close  to  the  amount  used  in  practise. 

Even  at  the  risk  of  repetition,  it  is  worth  saying  again,  that 
plastic  mortar  made  with  20  per  cent,  of  water  is  close  to  practise, 
and  will  give  regular  and  accurate  tests  if  put  into  molds  under  light 
pressure.  The  amount  of  this  pressure  does  not  seem  to  be  of  such 
great  importance,  but  20  Ibs.  per  square  inch  gives  rather  sharper- 
edged  briquettes,  with  about  the  same  variation  in  uniformity  and  the 
same  tensile  strength  per  square  inch.  This  is  equivalent  to  20  feet 
of  masonry,  which,  of  course,  is  more  than  practise  would  give ;  but 
the  tests  do  not  vary  to  any  extent  when  compared  with  those  made 
with  10  Ibs.  per  square  inch.  Therefore,  it  is  not  deemed  of  sufficient 
importance  to  sacrifice  good  manual  results.  Therefore,  20  Ibs.  per 
square  inch  pressure  and  20  per  cent,  water  was  adopted  about  i 
month  ago,  and  the  following  results  obtained  (Table  IV.). 

Whether  the  future  will  bring  sand  tests  to  greater  uniformity 
than  this  remains  to  be  seen;  but  it  is  believed  that,  in  this  way,  the 
sand-combining  qualities  of  cements  can  be  compared  with  accuracy 
with  one  another,  and  in  future  such  will  be  the  method  adopted  in 
the  cement  laboratory  at  McGill,  subject  to  the  modifications  of  our 
cement  committee. 


AMERICAN   CEMENTS.  133 

It  is  earnestly  to  be  desired  that  a  code  of  tests  be  formulated  at 
once,  and  all  members  urged  to  test  under  this  code.  Let  all  cements 
stand  or  fall  under  it. 

COMPRESSIVE   TESTS. 

These  are  doubtless  more  valuable  than  tensile  ones,  in  the  sense 
that  we  use  mortar  usually  in  compression.  There  are  several  rea- 
sons, however,  why  such  tests  are  not  really  needed :  — 

1 .  Because  the  strong  machinery  needed  would  not  be  generally 
available. 

2.  Because    the  compressive  strength,    after  all,  varies  quite 
regularly  with  the  tensile,  being  5  to  6  times  as  great  at  i  week  or  4 
weeks  and  gradually  increasing  to  9  to  i  o  times  as  great  at  a  year, 
because  by  this  time  the  cement  is  becoming  brittle,  and  has  attained 
its   maximum  tensile  strength.     This  is  more   particularly  true  of 
Portland  cements,  as  naturals  do  not  get  so  brittle. 

3.  Because  the  compressive  strength  of  cement  mortar  is  so 
great  that  we  need  seldom  concern  ourselves   with  it,  but  should 
rather  know  the  adhesive  and  tensile  strengths,  should  they  ever  be 
called  into  play,  and,  moreover,  the  strength  of  mortar  in  thin  joints 
is  much  greater  than  in  cubes.     Tests  on  cubes  always  go  higher  for 
small  cubes  than  for  large  ones.     (See  also  series   [IVfl]   tests  of 
mortar  joints  in  brick  piers.) 

TRANSVERSE   TESTS 

Have  often  been  advocated,  and  the  machinery  needed  may  be  quite 
simple;  but  there  are  two  objections  which  would  preclude  there 
being  any  great  value  in  such  tests :  — 

1.  Because  the  coefficients  of  rupture  in  transverse  testing  are 
known  to  be  at  fault  in  not  really  indicating  the  tensile  strength  of 
the  outer  layer  or  fiber.    This  could  possibly  be  avoided  by  determin- 
ing certain  corrections,  as  a  thesis  paper  to  the  Engineering  News 
pointed  out :  — 

2.  The  main  objection  is  that  a  flaw  of  a  very  slight  amount 
may  be  objectionable  in  such  tests  if  situated  near  the  tension  face. 
Any  cement  tester  knows  that  bubbles  will  occur.     They  may  be  very 
minute,  or  if  of  any  size  may  be  deducted  in  tensile  tests,  while  in 
transverse  tests,  who  could  determine  the  correction  to  be  made? 


134  AMERICAN   CEMENTS. 

Also  tests  made  show  that  if  tested  upside  down  from  position 
molded,  the  results  are  higher  than  when  tested  as  molded.  Alto- 
gether, this  method  of  testing  does  not  seem  to  commend  itself  to 
general  use. 

To  conclude  the  subject  of  ordinary  testing  for  commercial  pur- 
poses, and  with  the  addition  of  chemical  analysis,  where  available,  for 
scientific  ones  also,  the  following  seems  to  be  a  good  basis  to  work 
on,  that  4  tests  should  be  made  in  combination :  — 

1.  Specific  gravity  3.10  for  Portlands,  2.95  for  naturals. 

2.  Blowing  test.     In  the  absence  of  really  final  knowledge  on 
the  subject  to  continue  to  specify  pats  in  steam  at  i  i5°F.  for  four 
hours,  in  water  at  i  I5°F.  for  twenty  hours,  at  which  time  if  the  pats 
are  stuck  tight  to  the  ground  glass,  the  cement  may  be  considered 
safe,  while  if  it  has  loosened  from  the  plate  but  has  not  yet  cracked 
or  warped,  it  may  be  immersed  again  for  twenty-four  hours  at  1 1 5°F., 
or  else  placed  in  water  of  ordinary  temperature  for  four  weeks,  after 
which,  if  no  further  signs  have  developed,  the  cement  may  be  con- 
sidered safe. 

(3)  .Fineness :  — 

•  10  p.  c.  residue  on  No.  80  sieve    j   as  maximum> 
and  20  p.  c.        „         „      „  120     „        ) 

(4)  Tensile  strength  : — 

Portland.     Naturals. 

Minimum  neat  3  days  250  75 

„  „  i  week  350  100 

„  „  4  weeks          450  200 

I  to  I  and  3  to  I  sand  tests  with  20  p.  c.  water,  and  20  Ibs.  per 
square  inch  pressure  to  be  determined  by  tests  made  and  results  fur- 
nished within  the  next  year. 

SERIES    I. 

SPECIAL   TESTS. 

On  the  effect  of  fine  grinding:  — 

(a)  2  oz.  cement  passing  No.  120  sieve      .     .      Cement 
2  oz.      „     caught  on  No.  120  sieve  ^ 
2  oz.      „  „      „    No.    80  sieve   >-       .     .     Sand 

2  oz.  sand  ) 

tested  at  4  weeks  gave  165  Ibs.,  while 


AMERICAN    CEMENTS. 


135 


2  oz.  cement  passing  No.  1 20  sieve  .     .     .     Cement 
6  oz.  sand  .     .    Sand 


gave  121  Ibs.  tested  at  the  same  age. 

Thus,  if  in  the  first  instance  we  consider  all  but  the  finest  as 
sand,  then  our  result  is  only  35  per  cent,  higher  than  the  2d  mixture, 
showing  of  how  little  value  the  coarser  particles  were. 

(£)  No.  8  English  Portland  (very  coarse)  gave  in  ordinary  test 
414  Ibs.  i  week  neat,  528  Ibs.  4  weeks  neat;  but  when  all  the  parti- 
cles caught  on  No.  80  sieve  were  rejected,  the  results  were  393  Ibs. 
in  i  week,  484  Ibs.  in  4  weeks,  demonstrating  the  well-known  fact 
that  neat  tests  of  Portlands  operate  against  fine  grinding,  and  there- 
fore should  be  considered  only  in  connection  with  fineness  and 
specific  gravity. 

(c)  Equal  portions   (same  brand)   of  residues  on  No.  50   and 
No.  80  sieve  were  mixed  with  22^  per  cent,  water,  and  gave  262  Ibs. 
in  i  week  and  324  Ibs.  in  4  weeks,  which  is  very  surprising,  and  can 
only  be  accounted  for  on  the  ground  that  the  dust  of  cement  cling- 
ing onto  the  coarse  particles  was  sufficient  to  hold  them  together,  or 
else  that  the  mechanical  action  of  mixing  the  mortar  broke  up  many 
coarse  particles  into  finer  ones. 

(d)  To  show  the  superior  value  of  fine  cement  in  sand  mixtures, 
the  following  results  have  been  obtained  :  — 


Itol. 

2tol. 

Stol. 

Ordi- 
nary. 

Fine 
on  120 
Sieve. 

Ordi- 
nary. 

Fine 
on  120 
Sieve. 

Ordi- 
nary. 

Fine 
on  120 
Sieve. 

No.  2  Natural  i  week  20%  water  20  Ibs.  pressure  . 
No.  2  Natural  4  week  15%  water  tamped  
No.  2  Natural  4  week  15%  water  tamped  
No.  15  Natural  i  week  20%  water  20  Ibs.  pressure 
No.  15  Natural  4  week  14%  water  tamped  

114 

98 

US 
166 

190 
65 
123 
229 

77 

125 



Brand  A  Natural  4  week  20%  water  tamped  
No.  3  Portland  4  week  12%  water  tamped  

31 

39 

72 
47 
49 
82 
126 

121 
100 
109 
102 

188 

No.  3  Portland  4  week  20%  water  20  Ibs.  pressure. 
No.  9  Portland  4  week  20%  water  20  Ibs.  pressure. 

These  results  should  be  a  convincing  argument  to  users  of  Port- 
land cement  that  fine  grinding  is  worth  paying  for,  because  the  finer 
the  same  cement  the  greater  its  sand-carrying  value  is. 

The  only  partial  exception  in  the  above  results  is  No.  2  natural 


136  AMERICAN    CEMENTS. 

This  is  either  erratic,  being,  however,  duplicated,  or  if  not,  is  easily 
accounted  for.  An  underburnt  cement  is  easily  ground,  and  there- 
fore is  not  apt  to  be  well  ground  ;  very  easy  grinding  will  make  it 
fine  enough,  and  the  better  burnt  particles  being  a  little  better  burnt 
are,  therefore,  harder  and  escape  grinding ;  but  these  particles,  not 
being  very  hard,  are  probably  bruised  up  in  mixing,  and  form  the 
best  part  of  the  cementing  substance ;  therefore,  when  those  are 
sifted  out,  the  underburnt  fine  particle  has  not  as  great  a  cementing 
value  as  the  mixture  would  have  unsifted.  On  the  other  hand,  the 
coarse  particles  in  Portland  cement  are  much  harder,  and  are  always 
a  detriment  in  a  sand  mixture. 

SERIES    II. 

HOT    WATER   TESTS. 

(a}  No.  i  Natural  cement  neat,  2  months  old,  gave  when  tested 
the  following  results  :  — 

(1)  Water  at  temperature  52°  F.,  226  Ibs.  average. 

(2)  „       „  „         122°  F.,  250  Ibs.  average. 

(fr)  No.  i  Natural  cement  i  to  i,  2  months  old,  gave  when 
tested  the  following  results :  — 

(1)  Water  at  temperature  47°  F.,  125  Ibs.  average. 

(2)  „       „  „         1 1 8°  F.,  129  Ibs.  average. 

(c)  No.  4  Portland,  neat,  i  month  old,  gave  when  tested  the 
following  results :  — 

(1)  Water  at  temperature  65°  F.,  533  Ibs.  average. 

(2)  „       „  „         1 1 8°  F.,  61 6  Ibs.  average. 

(3)  »       „  »         186°  F.,  556  Ibs.  average. 

(</)  No.  4  Portland,  3  to  i,  i  month  old,  gave  when  tested  the 
following  results :  — 

(1)  Water  at  temperature  66°  F.,  81  Ibs.  average. 

(2)  „       „  „         183°  F.,  8 1  Ibs.  average. 

These  tests,  which  are  very  uniform,  indicate  that  for  either 
natural  or  Portland  cements  tested  neat  or  with  sand,  there  is  a  slight 
gain  in  strength,  by  using  hot  water  in  mixing. 


AMERICAN    CEMENTS. 


137 


The  advantage  being  that  for  exposure  to  frost  the  cement  will 
set  quicker  and  resist  the  frost  action  better.  By  referring  ahead  to 
frost  tests,  it  will  be  seen  that  cements  exposed  at  about  same  temper- 
ature (natural  cement  only  tested  with  hot  water  in  frost)  gave  much 
higher  results  when  mixed  with  hot  water,  b«ing  in  ratio,  94  to  o  for 
neat  cement  No.  I  Natural,  and  1 1 7  to  44  for  i  to  I  cement  No.  I 
Natural. 

SERIES    III. 

FROST   OR   EXPOSURE   TESTS. 

This  series  consisted  of  various  investigations  into  the  strength 
of  mortars  when  mixed  with  different  conditions  of  water  and  under 
different  exposures,  reference  being  particularly  made  to  frost.  All 
tests  were  made  in  quadruplicate. 

The  first  set  was  submerged,  after  24  hours,  in  water  of  labora- 
tory tanks. 

The  second  set  was  kept  on  damp  boards  in  a  closed  tank  for  the 
whole  period,  and  never  allowed  to  dry  out. 

The  third  set  was  allowed  to  set  in  the  laboratory,  and  then 
exposed  to  the  severe  frost  and  left  in  open  air  for  the  whole  period. 

The  fourth   set  was  exposed  in  from  8  to  10  minutes  to  the 


severe  frost,  and  left  there  for  the  whole  period,  except  to  take  them 
out  of  the  molds  when  they  were  set  or  frozen. 

Table  V  is  here  given,  showing  the  results  obtained,  and  accom- 
panying it  is  a  temperature  chart  showing  the  weather  to  which  these 
mixtures  were  exposed  during  their  whole  period. 


138 


AMERICAN    CEMENTS. 


TABLE  V. 

FROST  OR  EXPOSURE  TESTS.  SERIES  III. 

tn 
1 

3 

w 
M 

Nos.  3  and  4  showed 
irregular  and  injured 
fractures. 

§2 

O*M 

C.S 

!! 

.  >>  • 

oU  £ 
SSg 

•H.S 

Some  of  No.  4  ten- 
sion injured  and  No.  3 
compression. 

Mixed  with  water  at 
temperature  122°  F. 

Mixed  with  water  at 
temperature  1  18°  F. 

f 

jj 
'$ 

•o 

l| 

_Q 

No. 

of  tests. 

vO 

S 

* 

? 

•• 

N 

-t 

<s 

S 

S 

Natural  time  of 
set. 

X 

V 

^ 

^ 

v 

^S 

§0 

^0 
^> 

\ 

o 

vo 

^ 

N 

to 

co 

0^ 

C 

Time  from 
mixing  till 
exposure. 

22 

22 

22 

22 

22 

22 

v°? 

So 

22 
*bV 

S," 

^ 
% 

•b^ 

°^ 

A 

v§.°° 

£2 

r^  o 

OM 

o 

Temperature  of 
Exposure 
for  4. 

b 

o 

1 

ti 
O 

JR 

PO 

h 

°o 

fa 

T 

fa 

c^ 
+ 

b* 

^ 
+ 

fa 

o 

ui 

fe 

°0 

fa 
3? 
+ 

Temperature  of 
Exposure 
for  3. 

h 
°« 
1 

fa 

°^ 

fa 
o 
SR 

fa* 
o 

r 

fa 

o 

+ 

h* 

| 

O 
+ 

fe 

t 

fa 
<k 

+ 

H 

IB! 

73       42 
^J 

Q     £ 

•5    •£ 
^"•8 

Q     £ 

•S    -5 

"  0   ^ 

Si"^ 

«    £ 

•£    •£ 
72" 

41 

•s  •£ 

.  o 
•o  -"^ 

fa    & 
•< 

-C       JS 

M         to 

"*   O_^ 
.0  ^T 

£  3 

•5    •*= 
•*•    ^J- 
"  °J^ 

^""S. 
fe    <U 

•5    •£ 

vO        vo 

d 

Compressive 
Strength. 

•«*• 

O 

| 

1 

1 

I 

o 

1 

„ 

1     |     5§ 

1 

8 

1 

fO 

- 

i 

o 
^ 

| 

& 

§ 

- 

1 

1 

S 

1 

1 

Tensile  Strength. 

Exposure 
before    s  e  t- 
ting.       (4) 

s 

CO 

n 

5 

& 

0 

1»- 

* 

o 

h>. 

1 

Exposure 
after  set- 
ting.    (3) 

1 

1 

2° 

s. 

o 

do" 

o 

eg 

5 

Damp  air 
test. 
(2 

?t. 

I- 

| 

<p 

oo 

i 

s 

N 

5 

1 

•R 

N 

Water 
test. 
1) 

1 

rx 
t^. 

1 

5 

N 

2 

c? 

2 

y 

1 

s 

: 

s 

B 

* 

* 

s 

5 

6 
S 

e 

_3 

2 

S 

•T3 

M   C  *i 
ifl  rt 

ll* 

0 

0 
N 

o 

ro 

^"<3  ^ 

ill 

o 

I 

O 

i 

AMERICAN    CEMENTS.  139 

It  will  be  noticed  that  these  tests  were  purposely  made  in  cold 
snaps  so  as  to  make  the  tests  as  severe  as  possible. 

It  would  appear  improbable  that  mortar  immediately  exposed  to 
severe  frost  would  become  stronger  than  that  allowed  to  set  in  a  warm 
atmosphere,  but  the  results  of  all  the  Portland  cement  tests,  both  in 
tension  and  compression  (with  one  exception)  assert  it ;  and  also  that 
those  allowed  to  set  in  the  laboratory,  and  then  exposed  continually,  are 
the  weakest  of  all  the  four  conditions  treated  of.  This  would  go  far  to 
dispute  the  advisability  of  covering  up  mortar  laid  in  frosty  weather. 

The  next  deduction  from  the  Portland  cement  tests  is  that  lab- 
oratory tests  made  with  briquettes  submerged  give  higher  results  than 
can  be  expected  in  open-air  work,  and  therefore  that  engineers  should 
add  this  to  the  various  other  degenerating  contingencies,  such  as  bad 
mixing,  dirty  sand,  etc.  A  deduction  not  much  evidenced  in  the  table 
is  that  it  is  not  safe  to  lay  Portland  cement  mortar  below  o°  F.  because 
the  third  and  fourth  series  of  3  to  I  Portland  exposed  at  — 6°  F. 
gave  ocular  evidence  that  their  structure  was  injured,  and  the  test- 
pieces  broke  most  irregularly,  while  the  other  exposures  at  about  o° 
F.  gave  no  evidence  of  any  injury  at  all.  Coming  to  the  natural  ce- 
ment mortar  in  the  fifth  and  sixth  lines,  we  find  much  different  results. 
The  first  one  is  decisive,  and  is  that  this  particular  cement  mortar  can- 
not be  laid  in  zero  weather.  The  first  set  were  all  blown  to  pieces 
(except  the  cube),  which  surprisingly  stood  1,390  Ibs.  while  the  second 
set,  although  not  quite  blown  to  pieces,  all  showed  extreme  injury. 

The  most  peculiar  result  is  that  this  same  cement,  neat,  if  given 
a  few  hours  to  set  in  the  temperate  air,  will  on  exposure  to  the  frost 
attain  a  strength  highest  of  the  4  conditions  ;  this  is  quite  remarkable, 
that  while  the  Portland  cement  was  strongest  when  submerged,  the 
natural  cement  was  stronger  in  damp  air  and  strongest  in  frost. 

Indeed,  the  Portland  cement,  in  air,  for  I  to  I  mixtures,  was 
very  little  stronger  than  the  I  to  i  natural. 

All  of  the  natural  cement  specimens  exposed  to  frost  showed  a 
disintegrated  layer  on  the  outside  about  %  in.  thick ;  underneath  this 
the  structure  was  quite  sound,  and  doubtless  much  of  the  variations 
in  tests  is  due  not  so  much  to  a  weakening  through  the  whole  mass 
as  to  a  reduced  sectional  area. 

The  last  series  made  with  2  per  cent,  brine  in  mild  weather  for 
i  month  (exposed  at  +  7^°  F.)  showed  that  salt  increased  the 


140 


AMERICAN   CEMENTS. 


strength,  making  them  as  strong  as  others  were  at  2  months  when 
mixed  with  fresh  water,  and  also  again  emphasized  the  advantage  to 
this  natural  cement  of  open-air  tests. 

It  would  seem  that  either  hot  water  or  salt  are  therefore  very 
strengthening  in  their  effect. 

SERIES  IV. 

SHEARING   TESTS. 

This  series  of  experiments  was  carried  out  with  a  view  of 
obtaining  more  information  on  the  shearing  strength  of  mortar. 
The  method  adopted  was  as  follows  :  — 

Three  bricks  placed  as  shown  in  sketch  were  cemented  together, 
and  tested  at  the  end  of  one  month.  It  was  found  that  by  placing 
pieces  of  soft  wood  at  A,  A,  A,  an  action  as  nearly  as  possible  a  shear 
was  obtained,  and  gave  very  satisfactory  results,  the  pressure  being 
practically  concentrated  along  the  two  mortar  joints.  No  side  pres- 
sure was  applied,  because  the  desire  was  to  obtain  minimum  results 
where  friction  was  not  assisting. 

The  combined  effect  of  adhesion  and 
friction  can  easily  be  computed  if  the  ad- 
hesion and  superimposed  load  are  known. 

The  results  are  divided  into  lime- 
mortar,  natural  cement  mortar,  and  Port- 
land cement  mortar,  also  into  %  in.  and 
Yz  in.  joints,  also  into  flat  common  unkeyed 
bricks  and  pressed  Laprairie  brick  keyed 
on  one  side,  (i)  The  lime  mortar  was 
mixed  I  lime  to  3  of  standard  quartz  sand, 
by  weight ;  (2)  natural  cement  mortar  was 
mixed,  I  of  No.  2  natural  cement  to  i^ 
standard  sand  ;  (3)  Portland  cement  mortar 
was  mixed,  I  of  No.  5  Portland  cement  to 
3  standard  sand.  The  test  pieces  were 
chiefly  allowed  to  stand  in  the  laboratory 
at  a  temperature  of  55  to  65  degs.  Fahr.,  but 
one  set  of  natural  cement  mortar  and  two  of  Portland  cement  mortar 
were  duplicated  by  immersing  in  water  for  29  days,  after  setting  in 
air  24  hours  before  submersion. 


t 


\ 


t 


AMERICAN    CEMENTS.  141 

These  results  point  out  many  interesting  facts :  (a)  the  first  fact 
noticeable  is  that  the  results  are  independent  of  the  thickness  of 
joint ;  this  is  true  of  lime  and  cement  mortars.  (£)  The  next  one  is 
not  evidenced  to  any  extent  in  the  table,  but  was  quite  apparent  in 
the  testing,  viz.,  that  the  adhesion  of  the  mortar  to  the  brick  was 
greatest  when  the  mortar  was  put  on  very  soft,  and  least  when  the 
mortar  was  dry.  This  will  largely  uphold  the  use  of  soft  mortars  by 
masons,  albeit  their  reason  is  a  purely  selfish  one,  the  mortar  being 
easy  to  handle.  The  tensile  tests  of  cements  made  very  soft  are 
lower  than  when  the  mixture  has  the  minimum  amount  of  water  for 
standard  consistency.  But  for  adhesive  tests  the  case  is  evidently 
the  reverse.  It  may  be  here  mentioned  that  in  these  tests  all  bricks 
were  thoroughly  soaked  with  water  before  the  joints  were  laid,  (c) 
Coming  now  to  the  tests  on  lime  mortar,  the  shears  were  through 
the  mortar,  except  in  the  fourth  experiment,  and  therefore  they  are 
quite  independent  of  the  key  of  the  pressed  brick  on  the  surface  of 
adhesion.  This  would  point  out  the  fact  that  keyed  brick  are  super- 
fluous in  lime  mortar  joints,  and  the  shearing  strength  per  square  inch 
averages  about  io*4  Ibs.  per  square  inch.  The  tensile  strength  of  the 
same  mixture  at  the  same  age  was  30  Ibs.  per  square  inch,  and  the  com- 
pressive  strength  102  Ibs.  per  square  inch,  (d)  The  natural  cement 
mortar  showed  distinctly  that  its  adhesive  strength  was  not  as  great 
as  its  shearing  strength,  which  is  the  reverse  of  the  lime  mortar  tests. 
It  also  showed  that  the  keyed  brick  aided  in  some  unknown  way,  for 
the  results  on  them  are  three  times  as  great  as  with  the  common  flat 
brick.  Of  course  this  may  have  been,  and  probably  was,  partly  due 
to  the  different  surface  of  adhesion.  In  five  tests  out  of  twenty-one 
made  on  the  natural  cement  mortar,  the  mortar  sheared  through,  and 
the  average  of  these  five  was  97  Ibs.  per  square  inch,  which  gives  the 
shearing  strength  proper,  while  the  average  adhesive  strength  of  the 
thirteen  tests  in  air  which  came  loose  from  the  bricks  was  26  Ibs.  per 
square  inch  in  common  brick,  48  Ibs.  per  square  inch  on  Laprairie 
pressed  brick,  and  38  Ibs.  per  square  inch  on  Laprairie  pressed  brick 
for  three  tests  submerged  in  water  for  the  whole  period. 

This  would  show  that  the  adhesive  strength  is  nearly  twice  as 
great  on  pressed  brick  as  common  brick,  and  that  submersion  in 
water  had  a  rather  harmful  effect  than  otherwise  on  the  adhesive 
strength,  and  was  certainly  of  no  benefit. 


142 


AMERICAN   CEMENTS. 


3 


^ 

JJ 

rt 

"O 

1 

|||1  P| 

PfJlfag 

a 

H 

mortar, 
mortar, 
mortar, 
ck  (mortar  dr 

;;] 

ick,  two  shea 
ck. 

HfE!!! 

fl*fl°-j 

w  o  :f§5J=  "o 

ei!lllfl 

"C      'C      -Q 

9 

*5  *5  *5  "-Q 

-°             rO                C 

E      E      S      S 

« 

till 

I        P       1 

1   I 

I^^S 

S  S  °"? 

a?       n?       rt*       rt" 

•5  -5-5  * 
111* 

Illl 

2      5      * 

>         >         RS 

rt       rt       D 

•  si 

1    1    s 

I  1 

^      is      £      & 

flj        rt        rt        rt 
tt       •       0       • 

E   .  E   .  E   .  S  . 

5  s  i 

c     - 

._.'C_'C_'C_-C 

«<•< 

<5     <     H 

O     < 

<:'a<;'n<j^<'n 

if 

O>OO  10  O 

MOO 

°.      °. 

\O           ^          N            O^ 

J3           -2 

N          ro       00 

OO          M 

c        2 

tH 

M 

I    " 

|     i 

DO  \O    O>  10 

q       q       q 
oo       -4-      »o 

N          <S 

Q      o 

Illl 

1     i 

rx-H  0   0 

«?     o      ° 

°      9 

\q       q.      10      - 

'^    i 

^ 

M             O           10 

#     % 

O           fO        vO           f^ 

M  s 

is  Is  i  is 

i      ^      J: 

.h     | 

^                            V- 

>:     fa     »;     « 

•s    >   -s    ^ 

"a 

S  5  S  S 

c      c      c 

C         C 

n      c      c      c 

°  » 

1 

o| 

u}  ^-  in  in 

U 

fc* 

•C    a 

•°      0 

s  s 

I 

<<:«« 

<c    <J    pa 

03       03 

•<     <J     «     M 

1  £• 

*s 

>,-c 

**** 

»    X   X 

*    X 

»    »    »    » 

O    "O 

3    % 

»    »    JR 

x  * 

. 

^     Q, 

i 

C   C   C   C 

c       c       c 
rt        rt        rt 

cn     c/J     c/> 

Jc 
c3 

c      c      c      e 

Cfl       O)       C/5       CO 

g'g 

11 

"o 

/—  ^^«^s—  ^^-^«. 

~»~*~^* 

_^_  ^^^^.^^^ 

O  J 

1 

H 

N.*2  fl"c  0*2  B 

|c|g 

£!  sis!  sis 

<  M 

Illl 

*lllall 

l^ia 

'lilllilj 

AMERICAN    CEMENTS.  143 

The  tensile  strength  of  the  same  mortar  at  the  same  age  was  132 
Ibs.  per  square  inch  ;  the  compressive  strength  was  not  obtained,  but 
would  have  been  about  1,000  Ibs.  per  square  inch.  The  hints  to  be 
taken  from  these  tests  are  that  pressed  brick  keyed  on  both  s'ides 
will  give  much  higher  results  than  flat  common  bricks,  and  would 
probably  place  the  shearing  strength  of  such  joints  at  100  Ibs.  per 
square  inch,  and  make  it  largely  independent  of  the  consistency  of  the 
mortar.  Also  that  the  shearing  strength  is  very  much  higher  in  pro- 
portion to  the  tensile  strength  than  was  the  lime  mortar  shearing 
strength  to  its  tensile  strength,  but  about  the  same  proportion  to  its 
compressive  strength,  /.  ^.,  i  o  to  I . 

It  becoming  evident  that  the  thickness  of  joint  had  no  appreciable 
effect,  the  Portland  cement  mortar  tests  were  made  all  X  in-  thick. 
The  results  are  surprisingly  low.  The  adhesion  on  the  common  brick 
is  about  the  same  for  air  drying  or  submersion  in  water,  and  is  slightly 
less  than  one  half  that  of  natural  cement  mortar  tests  of  I  ^  to 
i.  This  is  a  significant  fact,  for  while  a  neat  tensile  test  of  No.  2 
natural  cement  4  weeks  old  is  268  Ibs.,  the  No.  5  Portland  is  459  Ibs. 
for  the  same  age,  and  a  3  to  i  No.  5  Portland  is  82  Ibs.  for  same 
age.  (See  table  of  general  laboratory  results.)  Thus  while  any  test 
of  this  cement  would  show  that  a  3  to  I  mixture  of  the  latter  would 
be  nearly  equal  to  a  i  y2  to  i  test  on  the  former,  yet  in  their  adhesive 
properties  to  common  brick  the  heavily  dosed  sand  mixture  was  only 
half  as  strong  as  the  natural  cement  mortar  with  a  smaller  dose  of 
sand.  We  might  easily  have  expected  this;  but  the  main  point  is: 
is  it  taken  account  of,  in  considering  the  comparative  values  of  these 
mixtures,  that  the  adhesive  strength  of  a  Portland  cement  mortar 
heavily  dosed  with  sand  is  low  as  compared  with  a  weaker  but  richer 
mixture  of  natural  cement  mortar  ?  The  shearing  of  Portland  mortar 
shows  that  the  adhesion  to  pressed  brick  is  greater  than  to  common 
brick,  but  not  in  such  proportion  as  in  natural  cements,  being  i  ^  or 
2  to  i  in  place  of  3  to  i  in  the  latter.  But  here  again  comes  out  the 
advantage  given  to  Portland  cements  by  testing  them  under  water; 
the  submerged  specimens  are  stronger  than  open  air  ones,  while  in 
natural  cements  the  reverse  is  the  case. 

Table  VI.  summarizes  the  results  obtained. 


144 


AMERICAN    CEMENTS. 


5   i 

<    o 

r  .       ^ 

52 


1 

1 

1 

i 

PO 

*m 

X 

00 

* 

32 

u 

s 

• 

°- 

f 

« 

o° 

1 

* 

, 

s 

& 

6 

11 

* 

q 

q 

« 

o 

1 

S 

q 

r 

? 

"N 

1 

s 

Jb' 

"x  o 

03 

5 

m 

I 

21 

i 

r  square  inch. 

il 

i 

s 

1 

i 

0* 

S, 

i 

"M* 

K 

„ 

£ 

«n 

8s 

a 

.SfS-c 

••> 

in 

vO 

in 

3 

"S^"0 

1 

1-1 

1st  signs  of 
failure  in 
mortar. 

in 

M 

* 

1 

H 

1 

III 

e 

ts. 
CO 

to 

« 

111 

ro 

N 

| 

M 
a*             u 

6* 

a* 

j*' 

• 

j 

tC.  «  vo  vS 

i 

00    M   -4-vO 

•  bo      £ 
"qs^.ja  ^ 

tx  N    OvO 

C«"    •          g 
ejn^oo" 

l-a  -i 

^,  n  ^-sS 

if  a 

* 

"5 

^s 

^S 

6 

& 

HB»? 

11 

i 

1 

1 

PO 

1 

i 

13 

"c 

® 

13 

13 

a 

"I 

S 

^  i 

5  «: 

•««        S» 

*      ^ 

t  I 

**     b 

IC^       >, 

r 

'Jf 

w  i« 

|.| 

Zi| 

32 

M    IT) 

No. 

i  Lime. 
5  Building 

•     2 

l^g 

E^ 

MM 

M    fO 

11 

AMERICAN    CEMENTS. 


145 


I 

9 

q 

f 

I 

o 

* 

^o 

tn 

5: 

6 

§ 

8 

1 

? 

9 

| 

\ 

~8 

lo 

i 

'1 

I 

{ 

1 

! 

i 

« 

£ 

I 

\ 

0 

1 

: 

| 

I 

w 

0 

fc 

00 

f 

4- 

S 

1/1 

1 

5 

| 

.1 

8 

8 

: 

ro 

! 

8 

i 

A 

rt 

s 

pj 
2 

i 

*o          rt 

rt 

(4 

!3 

A 

^    s 

q  .    M 

fe^  i 

^42         S 

V  •     * 

>    •       <« 

^iS  w  cr 

>>  M  to'" 

oo  bj)j;'B 

".SPrf"! 

*^§ii 

°°  .£?  o5  "" 

S|< 

ff-cJg1 
"g""ir'J3  o 

^^^  Sf 

r^l 

^=!y  "* 

00    H    ^ 

oo  n  ^ 

oo  n  ^.s 

06   M   -«•£ 

adC^R, 

<»  Z  ^8. 

5. 

8* 

a 

ft, 

SM 

«w 

Jd 

i 

| 

i 

1 

<u 

-i 
i 

1 

J 

2 

5 

* 

J 

No.  6. 

i  of  No.  5  Portland 
cement. 
3  Laboratory  sand. 

.  bO 

111 

£  "*  '3 

No.  8. 
i  No.  ii  Portland, 
i  Lab'tory  sand. 
Laprairie  pressed 
brick. 

No.  9. 

i  Lime. 
3  Lab'tory  sand. 
Laprairie  pressed 
brick. 

No.  10. 

i  No.  z  Natural. 
i%  Lab'tory  sand. 
Laprairie  pressed 
brick. 

s 

146 


AMERICAN    CEMENTS. 


SERIES    IV.  (A) 

THE    STRENGTH    OF    MORTAR    IN    COMPRESSION    IN  BRICK    MASONRY. 

All  engineers  realize  that  the  strength  of  mortar  is  much  less 
tested  in  cubes  than  in  thin  layers,  but  just  what  proportion  they 
bear  to  one  another  is  not  very  well  known.  The  following  experi- 


ments have  been  made  with  a  view  of  obtaining  this  information, 
(See  table  VII.). 

At  the  same  time  that  these  tests  were  made,  mortar  was  also 
made  into  test  pieces,  and  tested  at  the  same  age.  We  are  thus 
enabled  to  form  an  idea  of  the  relative  strengths  of  mortar  in  thin 
joints  and  in  cubes,  and  also  to  form  an  intelligent  opinion  of  the 
comparative  strengths  of  lime  mortar,  natural  cement  mortar,  and 
Portland  cement  mortar.  The  mortars  of  the  fourth,  fifth,  and  sixth 


AMERICAN    CEMENTS. 


147 


tests  are  identical  with  the  mortars  of  the  shearing  tests,  and  show  the 
same  clear  superiority  of  the  natural  cement  i  >^  to  I  over  the  Portland 
cement  3  to  I  when  used  in  this  manner.  Table  VIII.  summarizes 
the  results  obtained. 

Roughly  speaking,  the  lime  mortar  at  I  week  5  to  I  is  6  times 
as  strong ;  the  lime  mortar  at  I  week  3  to  i  is  14  times  as  strong; 
the  natural  cement  mortar  at  i  week  i  y2  to  i  is  4  times  as  strong ; 
the  Portland  cement  mortar  at  i  week  3  to  i  is  twice  as  strong 
as  the  same  mortar  tested  in  cubes  at  the  same  age. 

Referring  to  the  amount  of  compression  in  Table  VII.,  it  will  be 
seen  that  the  amount  of  compression  per  foot  is  much  less  according 
as  this  ratio  is  less ;  /.  e.,  the  less  yielding  the  mortar,  the  nearer 
does  the  strength  in  cubes  approach  to  the  strength  in  joints.  This 
is  to  be  expected,  because  the  more  yielding  substances  will  be  at  a 

TABLE  VIII. 


(i) 

(2) 

00 

(4) 
(5) 

(6) 

Strength  of  Mortar  per  square  inch. 

Loads  released 
at  17,500  Ibs., 
set  observed 
per  lineal  foot. 

In  joints. 

In  cubes. 

In  tens'n. 

245 
469 
400 
287 
968 

755 

40 

57 
57 

21 
250 

341 

17 

20 
20 

.01" 

•°5! 

.08" 

i  week  old,  mortar,  i  lime,  5  sand. 
3  weeks  old,  mortar,  i  lime,  5  sand. 
3  weeks  old,  mortar,  i  lime,  5  sand, 
i  week  old,  mortar,  i  lime,  3  sand, 
i  week  old,   mortar,  i  Natural  Ce- 
ment, lYz  sand, 
i  week  old,  mortar,  i  Portland  Ce- 
ment, 3  sand. 

43 

.00 

much  greater  disadvantage  when  unsupported  at  the  sides  than  if 
enclosed  in  a  thin  masonry  joint. 

In  the  second,  third,  fourth,  and  sixth  tests  at  17,500  Ibs.,  the 
load  was  released,  and  the  permanent  set  observed  was  as  given  in  the 
fifth  column  of  the  preceding  table. 

It  seems  probable  from  this,  therefore,  that  the  lime  mortars 
must  have  yielded  to  an  injurious  extent  before  there  were  any 
external  signs.  But  whether  this  was  the  case  or  not,  it  is  impossible 
to  say,  because  the  compression  was  quite  uniform  up  to  and  in 
many  cases  much  past  the  points  of  evident  failure. 

It  seems  fair  to  suppose  that  i  week  and  3  weeks  are  about  the 
minimum  and  average  times  which  would  elapse  before  the  maximum 
load  might  be  put  on  a  brick  wall,  and  when  it  is  remembered  that 


148  AMERICAN   CEMENTS. 

these  joints  were  less  than  ^  in.  thick,  the  amount  of  compression  in 
a  high  brick  wall  under  a  load  of  80  or  90  Ibs.  per  square  inch  is  seen 
to  be  very  great,  and  under  a  load  of  300  to  400  Ibs.  per  square  inch, 
a  brick  wall  50  ft  high  in  lime  mortar  would  not  only  fail,  but  com- 
press from  2  to  6  ins.  in  doing  so  —  the  compression  practically  all 
taking  place  in  the  mortar,  as  in  the  unyielding  Portland  cement 
mortar  the  compression  is  seen  to  be  very  small. 

The  second  part  of  this  paper  will  contain  tests  made  on  piers 
built  with  pressed  brick,  in  which  the  mortar  has  had  longer  time  to 
harden,  and  interesting  results  are  looked  for. 

The  brick  in  this  case  was,  as  mentioned  in  Table  VII.,  common 
building  brick.  The  photograph  given  illustrates  the  method  of 
testing  and  the  interesting  manner  of  failure  of  fifth  test,  in  which  the 
lines  of  least  resistance  are  clearly  defined. 

SERIES  V. 

EVAPORATION   AND    CRUSHING   TESTS   AND   EVAPORATION    AND 
TENSILE   TESTS. 

(a)  Evaporation  and  crushing  tests. 

This  series  had  for  its  first  intention,  information  on  the  com- 
parative and  actual  amount  of  evaporation  of  moisture  from  different 
mortars  made  with  different  cements,  but  it  soon  developed  into  an 
endeavor  to  obtain  some  relation  between  crushing  strength  and 
evaporation.  Any  law  on  the  matter,  if  there  is  any  general  law, 
will  of  course  take  years  to  demonstrate  ;  but  enough  has  been  done 
to  show  that  any  investigations  on  this  subject  will  be  fruitful  of 
results.  The  method  of  procedure  was  as  follows:  Mixtures  were 
kept  in  damp  air  30  days,  then  immersed  2  days  in  water  of  ordinary 
temperature,  then  taken  out  and  weighed;  they  were  then  kept  in 
the  warm  dry  air  of  the  laboratory  at  a  temperature  of  about  65 
degs.  Fahr.  exactly  2  days,  when  they  were  again  weighed  and  im- 
mediately crushed.  The  experiments  recorded  in  Table  IX.  were  all 
made  on  2  in.  cubes,  and  2  days  was  established,  because  it  was 
found  that  at  that  time  the  evaporation  was  practically  complete. 
Other  experiments  (not  recorded)  made  on  3  in.  cubes  gave  less 
evaporation  per  cent,  and  also  less  strength.  Attached  to  this  are  three 
diagrams ;  the  first  two  show  strength  and  evaporation  in  different 
mixtures  and  with  five  brands  of  cement.  The  third  diagram  is  the 


AMERICAN    CEMENTS. 


149 


product  of  the  other  two,  and  is  quite  worthy  of  inspection,  because  it 
would  appear  from  it  that  it  would  be  possible  to  estimate  fairly  and  ac- 
curately, without  actually  crushing  a  specimen,  what  load  it  would  bear. 

TABLE  IX. 

EVAPORATION   AND    CRUSHING   TESTS. 

No.  1 1  —  PORTLAND. 

SERIES  V. 


Mixture. 

Evap.  per 
cent,  in 
2  days. 

Crushing 
strength  per 
square  inch. 

Product. 

Max.  wt.  of 
2  inch 
Cube. 

t£) 

Column  4 
divided 
by  column  6. 

oz. 

Neat. 

1.48 

3925 

5809 

10.43 

22.16 

262.1 

I  tO    I 

3-4i 

2211 

7539 

10.12 

21.71 

347-3 

2  tO    I 

6.  20 

1031 

6492 

9-39 

20.66 

314.2 

3  to  i 

10.39 

544 

5652 

9.14 

20.30 

278.4 

4  to  i 

11.49 

43i 

4952 

8.92 

19.97 

247-9 

No.  10  —  PORTLAND. 


Mixture. 

Evap.  per 
cent,  in 
2  days. 

Crushing 
strength  per 
square  inch. 

Product. 

... 

(^) 

Column  4 
divided 
by  column  6. 

Neat. 

0.97 

4367 

4231 

9.84 

21.31 

199.0 

I    tO    I 

2.20 

3062 

6736 

10.23 

21.87 

308.0 

2    tO    I 

5-59 

1079 

6032 

9-43 

20.72 

291.1 

3  to  i 

8.61 

*94o 

8093 

9-iS 

20.31 

398.4 

4  to  i 

11.68 

5°4 

5886 

8.86 

19.87 

296.2 

*  One  day  older  than  others. 

No.  3  —  PORTLAND. 


Mixture. 

Evap.  per 
cent,  in 
2  days. 

Crushing 
strength  per 
square  inch. 

Product. 

wt. 

Neat. 

4-65 

1863 

8662 

IO.OO 

21.62 

400.7 

i  to  i 

4.10 

1875 

7687 

1O.I2 

21.71 

354-1 

2   tO    I 

5-67 

1417 

8034 

9.60 

20.97 

383-r 

3  to  i 

S.ii 

687 

5572 

8-95 

2O.OI 

276.2 

4  to  i 

12.56 

412 

5176 

8.88 

19.90 

260.0 

150 


AMERICAN    CEMENTS. 


No.  1 5  —  NATURAL. 


Mixture. 

Evap.  per 
cent,  in 
2  days. 

Crushing 
strength  per 
square  inch. 

Product. 

wt. 

Neat. 

6.76 

1888 

12762 

9.40 

20.67 

617.4 

i  to  i 

S.oS 

1437 

7300 

9-65 

2  1.  02 

347-3 

2    tO    I 

6.12 

988 

6046 

9-32 

20.57 

293-9 

3  to  i 

8-34 

575 

4796 

9-°5 

20.l6 

237-9 

No.  2  —  NATURAL. 


Mixture. 

Evap.  per 
cent,  in 

Crushing 
strength  per. 

Product. 

wt. 

2days. 

square  inch. 

Neat. 

5-93 

2575 

15720 

9-43 

2072 

758. 

i  to  i 

10.32 

703 

7254 

9.06 

2016 

359-9 

2    tO    I 

8-93 

810 

7233 

9.28 

2057 

352.6 

Reference  to  the  table  and  diagrams  will  show  that  the  evapo- 
ration increases  and  the  strength    diminishes  with   the  increase  of 

sand  in  the  mix- 
ture. This  is,  of 
course,  almost  self- 
evident,  but  the 
striking  difference 
in  the  amount  of 
evaporation  for  dif- 
ferent cements  neat 
is  unaccountable. 
This  difference  dis- 
appears as  the  ad- 
mixture of  sand 
increases,  and  we 
are  led,  therefore, 
to  conclude  that 

there  is  something  inherent  in  the  cement  itself,  which  aids  it  more 
or  less  in  holding  particles  of  water  in   suspension.     The   natural 


AMERICAN    CEMENTS. 


151 


cements  show  high  evaporation  neat,  so  also  does  the  No.  3  Portland, 
which  has  a  high  specific  gravity  (see  general  tables),  and  the  cubes 

of  which  weighed  more  than 
those  of  the  No.  10,  which 
evaporated  least.  We  can- 
not account  for  it  on  the 
ground  of  Portland  and  nat- 
ural, but  one  thing  is  evident, 
that  that  same  quality  which 
enables  it  to  hold  water  in 
suspension  also  aids  it  in 
holding  particles  of  sand 
together,  but  not  particles  of 
itself.  The  third  diagram 
showing  the  convergence  of  lines  on  the  I  to  I  mixture  is  very 
striking.  The  product  of  the  crushing  strength  of  a  I  to  I  mixture 
and  the  evaporation  per  cent,  under  conditions  named  is  practically 

CONSTANT.         This 

is  for  one  condition 
only,  namely,  32 
days,  with  access 
of  water  and  2 
days'  drying.  This 
means  in  plain 
words  that  we  may 
possibly  be  able  to 
test  with  a  balance 
instead  of  a  crush- 
ing machine. 

It  is  probable 

that  the  microscope  would  reveal  a  decided  difference  of  structure  in 
various  cements.  It  is,  of  course,  well  known  that  the  underburnt 
natural  cements  have  softer,  rounder,  and  more  easily  pulverized 
grains  than  that  produced  by  the  highly  burnt  clinker  of  the  Portland. 
It  is  possible,  therefore,  that  the  evaporation  qualities  of  a  neat 
cement  would  indicate  more  closely  than  anything  else  the  degree 
of  burning  practised,  independent  of  the  fineness.  It  will  be  noticed 
by  Table  II.  that  the  residues  on  sieves  afford  no  clue  to  the  density 


152 


AMERICAN    CEMENTS. 


of  the  mixture,  and  no  guide  to  determine  beforehand  the  evaporation. 
Neither  does  the  weight  of  the  specimens  vary  at  all  regularly  either 
with  the  crushing  strength  or  evaporation. 

It  would  seem  that  the  coarse,  angular  laboratory  sand  had  its 

interstices  just 
about  filled  up  with 
a  i  to  i  mixture, 
and  the  strength  of 
the  mixture  de- 
pended directly  on 
the  amount  of 
evaporation,  in  an 
inverse  ratio.  The 
Evaporation  dia- 
gram No.  4  is  the 
same  as  No.  3, 

except  that  this  product  is  referred  to  a  uniform  section  density 
(/.  <?.)  (^  weight  )  »  *ke  Diagram  is  practically  the  same,  showing 
that  the  variation  in  weight  of  test  pieces  made  practically  no  differ- 

x  (b)   Evaporation  and  tension  tests. 


^do 


ence  in  the  results,  /.  £.,  the  per  cent,  of  evaporation  determines  the 
strength  in  i  to  i  mixtures,  but  is  no  criterion  in  neat  ones. 

In  Table  III.  and  Table  IV.  the  per  cent,  of  evaporation  in  2 
days  is  again  given,  and  diagrams  are  plotted  showing  the  relation 
between  the  tensile  strength  and  the  weight  of  the  dried  briquettes 


AMERICAN    CEMENTS. 


153 


in  the  pressure  tests,  and  also  other  diagrams  showing  the  product 
of  tensile  strength  and  evaporation  plotted  on  a  base  of  weights  of 
briquettes. 

The  X  marks  in  the  diagrams  show  the  positions  of  tests  made 


with  20  Ibs.  pressure  and  20  per  cent,  of  water,  and  they  are  seen  to 
stand  at  prominent  and  usually  maximum  points  on  the  diagrams, 
proving  that  this  is  the  best  point  to  select  of  all  the  tests  made. 

It  will  be  seen  in  these  diagrams  as  in  those  of  crushing  tests, 


that   in  i  to  i  mixtures  the  variation  of  evaporation  and   strength 
combined  is  not  very  great,  but  not  so  close  as  in  the  former  tests. 

The   3    to  i    tests    are  very   erratic,   as  might  have   been   ex- 
pected with  different  per  cents,  of  water  and   different  amounts  of 


154 


AMERICAN    CEMENTS. 


pressure.  It  is  evident  that  each  cement  has  distinctive  qualities  of 
its  own,  because  with  the  same  weight  of  briquette  the  strengths 
vary,  and  this  brings  up  the  important  point  that  in  sand  tests  the 
strength  ought  to  be  referred  to  some  basis  of  weight  of  briquette, 
because  a  slight  variation  in  weight  seems,  from  Table  IV.,  to  affect 


the  strength  very  much.  It  would  not  take  much  evidence  to 
determine  the  average  weight,  and  all  tests  could  be  reduced  to  this 
by  multiplying  by  (^  weight  )*  which  would  change  the  section 
density  to  a  standard. 

SERIES  VI. 

SUGAR   TESTS. 

Sucrate  of  lime  is  soluble  in  water,  and  it  was  chiefly  a  matter 
of  interest  to  see  the  effect  of  sugar  on  cements  in  weakening  them, 
because  it  has  been  asserted  by  several  writers  that  the  reverse  is 
the  case ;  one  investigator  several  years  ago  showed  by  tests  that 
from  y2  to  i  per  cent,  of  sugar  would  in  4  to  6  months  give  a  gain 
in  strength. 

Sugar,  in  these  tests,  2  per  cent,  of  the  amount  of  cement  (by 
weight),  was  used,  and  the  diagrams  attached  sufficiently  indicate 
the  results.  In  the  Portland  cement  the  strength  ranges  closely  at 
50  per  cent,  of  the  ordinary  strength  as  far  as  6  months,  while  with 
the  natural  cements,  the  sugar  effect  was  overpowering.  After  I 
week's  immersion  the  briquettes  showed  signs  of  cracking,  and  as 
time  went  on  became  completely  checked,  and  expanded  so  much  as 


AMERICAN    CEMENTS. 


155 


to  give  practically  no  tests.  This  is  further  evidenced  by  the  upper 
surface,  which  was  protected  by  a  coating  of  iron  deposited  from 
Montreal  water,  being  intact,  while  the  checking  was  greatest  on  the 
bottom  where  the  water  had  free  access. 

The  lime  mixtures,  kept  in  open  air,  showed  encouraging  results 
for  2  months,  and  seemed  to  prove  that  the  use  of  sugar,  in  lime,  as 
practised  in  India,  was  beneficial ;  but  the  3,.  4,  and  6  months'  tests 
disprove  it.  Altogether,  it  seems  evident  that  this  much  or  more 
sugar  would  be  damaging  in  its  effects  on  any  kind  of  mortar  in  any 


n 


£tt^*fc 


•*?&- 


•7 


tffc 


•A**  V 


situation,  and  it  is  extremely  doubtful  whether  any  sugar  whatever 
would  have  other  than  a  weakening  effect. 

In  concluding  this  paper,  the  author  cannot  but  help  feeling 
that  he  is,  as  it  were,  dipping  just  on  the  surface  of  a  vast  subject, 
and  that  the  more  one  finds  out,  the  larger  the  unknown  fields 
beyond  appear. 

In  any  efforts  that  have  been  made,  the  frequent  manual  aid  and 
more  frequent  sound  practical  advice  of  Mr.  J.  G.  Kerry  have  been 
of  much  service,  and  here  is  the  place  to  acknowledge  it. 

The  endeavor  has  been  to  find  out  anything  of  practical  use  to 
the  engineering  profession  ;  and  if  any  points  raised  here  will  fulfil  this 
desire,  the  object  of  this  paper  will  be,  in  the  main,  accomplished. 


156  AMERICIAN    CEMENTS. 

PAPER    II. 

FROST  TESTS. 

IN  a  previous  paper,  read  before  the  society,  the  writer  promised 
to  place  before  its  members  the  results  of  certain  frost  tests  which 
were  being  made  at  that  time. 

They  are  now  given,  in  hope  that  they  may  be  of  some  interest 
to  those  engineers  who  are  contemplating  the  building  of  cement 
mortar  masonry,  or  cement  concrete  in  cold  weather. 

Method  of  procedure.  —  The  briquettes  were  all  made  in  the 
same  manner,  the  I  to  I  mixtures  having  1 8  per  cent,  of  water,  and 
the  3  to  i  mixtures  1 5  per  cent,  being  purposely  greater  than  the 
amount  used  in  ordinary  laboratory  tests,  so  as  to  get  the  mortar 
softer,  and  resembling  more  closely  the  condition  in  which  masons 
use  mortar  in  ordinary  construction,  as  the  effect  of  frost  may  be 
greater  on  soft  mortars  than  on  dry  ones. 

The  briquettes  were  all  rammed  into  the  molds  in  3  layers,  and 
the  briquettes  to  be  subjected  to  frost  tests  were  immediately  put 
outside  on  a  window-sill.  In  a  few  hours,  after  the  briquettes  were 
frozen  hard,  they  were  removed  from  the  molds,  and  left  exposed 
on  the  window-sills  for  two,  three,  or  four  months,  care  being  taken  to 
keep  the  snow  swept  off  so  as  to  allow  the  frost  to  have  its  full  effect. 

The  tables,  given,  speak  for  themselves,  and  probably  each  en- 
gineer will  draw  special  conclusions  of  his  own ;  the  writer  will  only 
mention  a  few  points  that  seem  obvious  to  him. 

I.   FOUR    MONTHS   TESTS. 

It  would  appear,  from  these  tests,  that  it  is  quite  safe  to  build 
masonry  work  in  November,  in  Montreal  climate,  when  the  materials 
are  mixed  and  exposed  to  the  air  at  about  the  freezing  point.  The 
proportion  which  the  strength  of  the  frost  tests  bears  to  the  sub- 
merged ones  is  about  that  which  would  be  obtained  under  the  most 
favorable  circumstances.  The  briquettes  were  all  firm,  smooth,  and 
hard  on  the  surface,  and  although  subjected  to  4  months  of  severe 
frost  in  an  exposed  position,  they  did  not  seem  to  have  been  at  all 
damaged. 

II.    THREE   MONTHS   TESTS. 

These  were  all  made  in  December,  and  the  coldest  days  were  pur- 
posely selected.     Yet  the  only  briquettes  which  were  blown  in  pieces 


AMERICAN    CEMENTS. 


157 


M  M  M    a 

„* 

Date  of 

MOMOWOO^OMnS 

«         M         ON       ^  § 

Exposure. 

O^ 
| 

K 

\O  •*•   (0   M    O  vO    OO  ONOn  4".  00 

Ui          K)          10    3    M 

•e 

if 

;:8A^xCcc-xC 

H                   On         ON 

i 

S  P 

XI    10  00                 M    ON  ONtn  00    OQ 

tO           K)                         w 

j 

3^- 

J 

CCCSJ33sMs?: 

°!  *!     8~ 

p 

'     1 

H 

El 

1 

0         0         0         S" 

Mixture. 

O 
c! 

W 

ooooooooooo 

g; 

o"booooooMooo 

0? 

ON        ON        ON       on 
%      %       *b      ^0 

Lab. 
air. 

il 

i 

% 

Lntntntntnuil/i   ON  ONCn   ON 
4»  4>-    tOOnxlxlvO^.    K>    OOUl 

ooooooooooo 

S 

S^   «&    S"   •& 

Water. 

al 

>. 

|| 

M     O 

rtT 

ON 

*b 

tn  Cn  On  t/t  on   ON  ON  ONOn  On   ON 
ON  OO  O0x|  x|    »H    O  OO    ONXJ  un 
OOOOOOOOOOO 

O 

o       o       o       o 

l! 

d    C 

C          ?NJ 

^0 

MO 

1  ?  %  1 

=4.ai 

il 

^O    O    O  O   O    O    O  °O    O    O^O 

2    ^ 

N 

00 

XI  vO  vO    OOXI    M  vO    OO\O  x|    to 

NO 

°x        °x      ^x        °x 

Time  elapsed 
from  mixing 
to  time  of  ex- 

x 

*5 

posure. 

K   H 

C 

o   W 

liiw   M^-^O-^I    Nwdo'.S 

•*- 

on       ^       oo       oo 

*.        ob       O        (o 

S? 

^3     CO 

M              ^             (0               M 

1 

B 

I 

Iff 

| 

H 

^1 

xf<SStU^SoO?8x5 

ON 

XI        'S         O          ON 

il 

1 

W 

M 

SB 

^-—^  xx  -*^_^ 

^^^~^~*^~^ 

OO 

VO 

-f^ 

0         C   O  ,Jp   ZTZryn 

k°-J-ffJl 

f  £|f  I  ifij 

|lf§|5||l 

• 

*z 

"<  n,       ^  O-"1  ~rt 

°  S?4  o-r*  ^  p.™  o 

• 

0^135      ft       N  ^*    0 
V'S-       §?w><?O- 

•tf'f'ftl 

158 


AMERICAN   CEMENTS. 


o3 

g 

2             M       °                     Ml                O«            rt'.'-'d            ^        ^             O,S 

| 

Cfl 

g*i        *-u^                    "c                ^*J-Aiu'rtIi3            ">        &           "O*Oaj 

Js    «a2                   22^0  Ja  8   ^-g   -g      SSff 

Q 

W>»     £5?*j                 -             o"°^Si<-ic>4-'     'o                     if  "^  D 

| 

g"°       'Qln-5)                      "^             >*<3'*'T30'£'S)        **   §"        0*             C>"5 

a 

2§       1   C^                      |  §  o  0^'S  «  rt^"^         =c         C     .    Q|        « 

o 

•g^2-.2g               Wo3  —  sj-LQ^Tjto'ort     raot3bow)2^JJS 

K 

02^3'!"          ^s^^^B^  |  {=J2    |2K§ae3:s  p  1*8 

02 

• 

'^  'o         w   ^T?                      ^CT1            '(flM°<0>VOO'<0         O         §             ~S 

I 

o 

||  Jig         §  *j     ^-s  «"5  <«  u^J^^^-o  l"*s 

*+ 

8 

•S3    o*-S  "         ^!s      ^  °  5*2  c'a  "Hll'Sl   Jr!'w> 

M 

05  'M        ^  rt  ^    .                 7   rt             -^  pC  ^  o,"**       "5        **rt^«nJjM        H    -S 

1 

s 

M 

M 

i 

M 

M  fill  il               dl 

M         c/3     fti               <            H         c«H            c«Q     Q         O 

w 

tl 

.  o 

1 

| 

M    ^ 

0          0    ro        M 

R. 

S    C»M^      vS'S'         3;$    y    ?^ 

g, 

H   o 

1 
O2 

W  | 

Hs 

Tensile 

1 

| 

MM 

S 

1      o^         »»            -    *     .« 

J 

§H 

•aansod 

-X3  JO  8UU1  0? 

Suixiuz  uiojj 

v      v^     ^ 

ts 

V                      V                                       V 

V              V     V      ^                  ^V                               M\X             V              V     V. 

k 

vO 

S     U 

pasdBjaamtjL 

f          (^ 

O    O 

O    O                                             O 

O 

LL]     £H 

a    £  . 

O          ^s«X,       O 

Q 

O         O    N^\^X            O    O                      n£x.O          O          O    O 

MS 

ri     Cti 

^  ""o  *S  '^ 

ts»        O    C1*       vO 

cr 

tx         O^  -^-00                 ^    ^                    00    IN,         O^         t-^sO 

0 

*    Q 

H     g* 

+   ++   + 

+ 

+    +++       ++          ++    +     1   1 

+ 

gs 

I! 

4 

O          O    O          0 

% 

O          OOO                OO                     OO          O          OO 

s 

3 

11 

O 

O          OOO                OO                      OO          O          OO 

o 

V. 

O       \O  fioo             co  -^                 co  in      to       O  *H 

OT 
W 

a.*® 

x5        »nv5        m 

\25        m  ^  ^           \o  vO                  in\o        in       mo 

Jn 

H 

i  | 

G 

SI 

•q?i 

vO        \8  vO*       vO 

O 

S      S%°in          ^1                Vg.      5      °S>^ 

S 

t> 

O» 

M               M      -               M 

ir> 

MMMM                         MM                                  MMMMM 

2 

•aanjxin 

2222 

2    222       22          22    2    22 

s 

PQ 

M               MM               M 

6 

m        f>roro              ro  ro                    fo  «        m        ro  -o 

rt1 

n 

*c3 
I 

<£              0^      0^ 

•c 

o8      o2o86^         o^o8               ^o8      o8      0^0° 

1 

b| 

£ 

i 

O        t»j  mo            vO  N                       «        ro       N   t-s 

S  V 

j 

V              V     V             V 

(S 

e  • 

.2 

8     <*>  ^    8 

• 

8     fo88       NM5          J?£>N>SM- 

i! 

• 
'3 

o       o           o 

1 

So             °M°«               °«0                                                                °N 

(•j  jadBj  asg) 

M      ^  N        in 

*s 

«     •*-«         «o^             22      2      jos 

pUBjg  jo  '0^1 

s 

1 

> 

•ajnsodxg 

•    -J           .   M         M 

Q 

Q 

AMERICAN   CEMENTS. 


159 


re      M               N       to  "jj1 

in  Q-      vO                  •*>•        «->   3 

H      P 

01            *.  3 

Date  of 

Exposure. 

> 

No.  of  Brand. 

I 

0              vO                     CX)       W 

en             M 

(See  Paper  I.) 

8, 

Wo     "o 

MM                       to          0 
Ln                 Os)                         O           O 
>.                    X                         %.            X 

c  * 

| 

0$ 

si' 

? 

"o              -o     °o 

No         "o 

3 

H 

00 

< 

°,     I       \  I 

1 

°.     ^ 

^3 

(6 

1 

vO 

00                    00 

1 

0             0 

Mixture. 

« 

5 

| 

S 

(iJ              o"                  -5       w* 

O                O                      O          O 

S 

!5          ? 

Lab. 
air. 

? 

CJ 

M 

I  I 

3 

CM 

o 

w 

"*o           o               o       o 

O 

-o          », 

Water. 

ll 

M 

C/5 

o 

o 

it      t  i 

"o           o             °o       o 

1 

t    J 

!? 

5'* 

i;  p 

> 

0 

w 

% 

o 

O              vj                      o       4^ 

o           o               o       o 

so 

'oo           "o 

|!||| 

c 

*  •  '  *  2, 

y 

_)_ 

4. 

1     +      +  + 

4- 

1     + 

O       j 

H 

ON 

M                      OO                           UT            W 

^ 

W                  00 

*i'^  S>  3 

H 

o 

o 

o           o               o       o 

"o 

o           o 

•  pi    >o 

K 

M 

^ 

-, 

^51         °x   51 

-, 

a,          <> 

Time  elapsed 
from  mixing 
to  time  of 

exposure. 

H 

£ 

g 

O 

* 

^ 

ft       S3 

u 

•s     « 

I 

3 

2. 

w 

OO               K> 

i! 

1 

§ 

M 

3  o 

?d 

HO            £     > 

sr^-«>3 

00 

losb    ||Ii|s^| 

Is*!! 

H 
S 

^ 

'  ijpt  s|l|;'l  1 

gt^llS^ 
<^2.N  o  »L 

ST*  H*        Q*     o.  fp      3      2 

5? 

pgp-i   *  El-  1-3  1*  1 

~5  2! 
o"5"      ^ 

O    ( 

s  f. 

s|^     fllfl  ^ 

3  »  0-3 

I 

|sls     t|s  ^  ? 

^  Is- 

S§  pg          VS8£     1 

6ilf     ?  fft  1 

-8   <;"" 

3*       3   ST* 

cn 


160 


AMERICAN    CEMENTS. 


8 

CO 


c    o 


UOMd 

-xa  jo  aunj  <n 
Suixiui  tuoaj 
ai"KL 


m 


io 


jo  -c 


•ainsodxg 
jo  a;BQ 


i 

XI  -2   3  £ 


^S     S, 


*  ^ 

vO       m 


X 


II 

S3&-S 


v 

in       t^. 


M  0 

vO        in 


o       o  o       o 


22       22 


AMERICAN    CEMENTS. 


161 


% 
o 

<s   &     sgf 

o       003 

Date  of 
Exposure. 

No.  of  Brand. 

1 

^ 

vO          00              W 

Ln         K> 

(See  Paper  I.) 

M 

< 

§. 

1 

-    "°      8° 

"0 

a 

Og 

1 

B 
8, 

1,      "'x 

p 

1.1 

to 

J3  ^ 

c1 

o 

°l    °>.      8, 

J 

O      "V. 

S* 

'  I 

? 

00              0 

1 

0         0 

Mixture. 

w 

| 

0, 

<*       *              ON 

ON 

%  ^ 

Lab. 

1 

0 

O          O                O 

air. 

3§ 

H 

i 

w 

o 

O          O              vO 

o       o            o 

*0 

»o"o 

Water. 

perature  at 
}  of  mixing. 

<-N 

it 

O    ^ 

% 

*"!>       o           o 

a 

O          M 

o       o 

1? 

rj 

o 

?° 

W 

i 

w 

* 

4-        4k 

IPlI 

g  V 

tn 

o 

0          O                 O 

«£ 

O          O 

S  A  0-S"? 

X    -« 

'  ^  ?  3  g, 

3  o 

5' 

_j. 

§     H 

O      |3 

n 

N 

vO           M                 £ 

o 

o    n 

S.g-^0 

Hj        • 

| 

o 

00                 0 

0 

0          0 

'  8-  ? 

W     ^ 

* 

°i  ^     <^ 

^ 

Time  elapsed 
from  mixing 
to  time  of  ex- 

0    ^ 

j3* 

posure. 

•^          Q 

i 

a  r* 

N 

^ 

H 
OO 

5    &       2 

8 

i3  s 

|j 

g 

o  « 

3 

| 

S. 

^ 

R 

f 

*>  ^ 

I 

3 

0 

<P    8       t*> 

N         *•               vO 

1 

5  2 

|| 

52 

I 

C   "^ 

n> 

|l 

^ 

£ 

iFo  i^^e,-*3 

C/3       CO 

oo 

5' 

g  |^||||| 

nlll 

vo 

~ 

w'^.o'rc  o^j  °  "* 

o  o"w  § 

1 

9* 

Itltlfft 

lipijn 

g-  ?  Sic 

y  I 

afg*    o1 

d 

M     S     *t*  O* 

2  §    "* 

r 

£1     ^*  3"  3  o 

s  1*5* 

i" 

!T      v      »>  S 

-°-  s.  §g. 

If  ^ 

i 

1  1  ir 

3         5" 

F 

162  AMERICAN    CEMENTS. 

were  those  made  from  two  very  inert,  slow-setting,  poor  Canadian 
natural  cements.  The  two  other  natural  cements  (one  Canadian, 
the  other  Belgian)  were  quicker  setting,  and  stood  the  test  well. 
With  the  Portland  cements,  the  diminution  in  strength  is  more  ap- 
parent than  real,  the  proportion  of  90  to  164,  which  is  the  average  of 
ii  brands,  is  really  between  briquettes  %  to  J/&  in.  square,  and 
briquettes  i  in.  square,  the  frost  specimens  being  weathered  off. 

It  is  reasonable,  however,  that  a  briquette  I  in.  square,  exposed 
on  3  sides  to  the  direct  action  of  the  frost,  is  rather  more  severely 
tested  than  mortar  would  be  if  placed  in  a  wall,  even  the  bottoms  of 
the  briquettes  resting  freely  on  the  stone  window-sills  were  largely 
uninjured,  and  the  centers  of  all  the  briquettes  appeared  uninjured. 
As  a  result  of  these  experiments,  the  writer  would  feel  perfectly  safe 
in  laying  cement  mortar  in  December,  with  Portland  or  active 
natural  cements,  in  weather  10  to  15  degs.  above  zero,  and  in  the 
most  exposed  situations,  expecting  in  the  spring,  to  find  %  to  l/2  ins. 
disintegrated  at  exposed  joints,  and  needing  re-pointing,  or  better 
still,  the  pointing  could  be  left  till  spring,  and  done  once  for  all. 

III.    TWO    MONTHS    TESTS. 

These  tests  were  much  more  severe  in  their  nature,  the  sand  and 
cement  were  exposed  for  hours  in  the  open  air,  in  small  quantities, 
until  they  were  absolutely  down  to  the  temperature  of  the  outer  air, 
and  in  the  cold  water  and  salt  water  series  the  water  was  also  exposed, 
until  it  was,  in  three  cases,  actually  below  the  freezing  point,  being 
in  a  slushy  condition. 

These  materials  were  put  together  in  the  laboratory,  as  rapidly 
as  possible,  and  exposed  again  at  once,  the  usual  interval  being  about 
6  minutes,  and  the  actual  temperature  of  the  mortar  just  before  ex- 
posure having  reached  about  33  or  34  degs.  F.,  while  in  the  hot  water 
tests  the  mixture  rose,  on  an  average,  to  58  or  60  degs.,  just  before 
exposure,  which  was  just  about  laboratory  temperature. 

The  experiments  are  hardly  extensive  enough  to  be  fully  con- 
clusive, being  made  only  on  7  brands  of  cement,  but  they  point  clearly 
to  the  advantage  of  the  use  of  salt.  Those  briquettes  made  with  salt 
showed  good  strength  and  little  injury ;  although  made  with  mate- 
rials, at  low  temperatures  exposed  in  severe  cold,  they  seemed  to  be 
chiefly  affected  only  on  the  surface. 


AMERICAN    CEMENTS.  163 

On  the  other  hand,  the  use  of  hot  water  does  not  seem  to  be  of 
any  advantage,  particularly  in  Portland  cements ;  a  reason  advanced 
by  one  write!  for  this  fact  was,  that  the  bringing  together  of  mate- 
rials in  a  mortar,  at  widely  divergent  temperatures,  exerted  a  prejudi- 
cial effect  on  the  cement,  hindering  proper  crystallization,  and  that  the 
use  of  materials,  at,  as  nearly  as  possible,  the  same  temperatures  would 
produce  more  rapid  and  stronger  action.  The  effect  of  hot  water  on 
natural  cements  is  not  so  disappointing,  but  does  not  show  much 
increase  over  the  strength  of  similar  specimens  made  with  cold  water. 

The  general  result  of  these  experiments,  to  the  writer's  mind, 
points  to  the  idea  that  in  any  weather,  in  winter,  not  extremely  cold, 
say  not  lower  than  -f-  1 5  degs.  F.,  masonry  work  can  be  laid  with  cold 
sand,  cold  cement,  and  cold  water,  provided  the  natural  time  of  set 
of  the  cement  is  not  more  than  5  or  6  hours,  and  that  by  the  addi- 
tion of  about  2  or  3  per  cent,  of  salt  to  the  water,  the  same  work  may 
be  done  in  weather  down  as  low  as  zero,  which  is  as  cold  as  men  will 
work.  The  disintegration  will  not  extend  probably  deeper  than  % 
to  y2  ins.  —  the  remainder  of  the  mass  being  quite  sound. 

By  what  process  cement  sets,  after  it  has,  in  a  few  minutes,  been 
frozen  solid,  and  remains  frozen  for  months,  the  writer  will  leave  to 
others  to  explain,  but  set  it  certainly  does,  without  ever  having  been 
thawed  out. 

The  following  able  and  complete  paper  makes  clear  many  of 
the  points  of  the  subject  under  discussion,  and  we  are  confident  will 
be  appreciated  by  engineers  and  cement  testers  generally. 

By  the  courtesy  of  its  author  we  are  permitted  to  print  it  in  full, 
together  with  drawings  of  his  automatic  cement  testing  machine, 
which,  from  its  excellent  construction,  seems  to  leave  little  room  for 
improvement. 

REQUIREMENTS     FOR     TENSILE     STRENGTH     IN 
CEMENT  SPECIFICATIONS. 

BY  J.  M.  PORTER,  ASSOC.  M.  AM.  SOC.  C.  E.,  PROFESSOR  OF  CIVIL, 
ENGINEERING,  LAFAYETTE  COLLEGE,  EASTON,  PENN. 

ON  a  recent  piece  of  work  embodying  some  4,000  cu.  yds.  of 
concrete,  of  which  the  writer  had  charge,  the  cement  specifications 


7e  samp/e  ofiCement  ——  — 

o//te  method  promoted  iy  Comm'iffee  cf  '' 

not.  ffo-citren  daft.  Am..Snr  r.  F  —  . 

U 

0 

1 

i 

1 

V 

1 

1 

«5 

6^ 
I; 

^t 
h 
?> 

u 

it 

*     5" 

S 

i 

f 

'I 

florf-  fl/l  moutdt  and  sand 
flm  .  Joe  C.L  .  Jfbttfforct 

/J  0/7  /#<  •TOT 

/«/•  $fandinf 

i1 

\     i 

If! 

fa,fl>anKl 
J,  /,*,»»,  C/,/. 

1 

1 
fl 

i 

1 

1 

ii 

if 

1^ 
1 

lii 

11 

.5 

.n 

Ii: 

•\   * 

i 

1 

^  ^ 

*j 

1 

1 

1 

1 

t  $  Ss 

4i 

^ 

II- 

II! 

i 

} 

II 

1 

i 

! 

I 

1 

II 

'!« 

1^ 

3 

i 

i 

1 

i  i 

^  i 

I 

§ 

I 

i 

1 

sl*1 

Us! 

>0 

I 

II 

\   t 

1 

! 

t  f 

f 

? 

IX 

s 

I 

1 

£3 

/»  ate 

1  1' 

^     ? 

i{ 

; 

;  * 

« 

$* 

• 

5 

J 

! 

$ 

|V    <• 

t      ? 

$ 

^? 

^  * 

; 

5 

* 

ii 

\ 

I 

4>! 

I      ^ 

\ 

•5     ^> 

? 

* 

\ 

: 

W 

\ 

A 

$ 

*    * 

.-  . 

^ 

^ 

5 

*     * 

-$ 

b 

•5-2 

?    » 

M 

t 

5  $ 

51 

?    * 

^ 

. 

5    t 

5 

5 

s 

; 

5 

ll 

•?     * 

1 

; 

5    5 

5 

£ 

- 

\ 

Ii 

» 

?    ; 

» 

• 

ki  1^- 

£. 

5^ 

>* 

•si 

I 

^ 

s. 

0 
V 

1 
•c 
q 

XJ 

I  jl 

1 

Ii 

p 

)i 

8* 

t 

1 

T'.a/oytttt  Co/left 

'  yr*sTo»  A 
j-aifofftf 

]fKffirfftHr+ii* 

''HttMlte-roH  0  C 

8* 

1 

UNIVERSITY 

AMERICAN    CEMENIfCAUFORHs  165 


called  for,  among  other  requirements,  a  tensile  strength  of  1  50  Ibs. 
for  one  cement  to  three  sand  mortar  at  the  age  of  seven  days.  The 
first  shipment  of  cement  received  on  the  work  was  sampled  and 
tested,  and  failed  to  fulfil  the  requirements  for  tensile  strength,  and 
the  contractor  was  so  notified.  At  the  request  of  the  cement  manu- 
facturers their  representative  tested  the  cement  with  a  result  about 
15  per  cent,  below  the  result  first  obtained.  The  manufacturers 
again  requested  that  a  representative  from  a  certain  testing  labora- 
tory be  allowed  to  make  a  test.  This  request  was  also  granted,  and 
the  result  obtained  was  over  50  per  cent,  in  excess  of  the  first  test, 
and  brought  the  cement  beyond  the  requirements  of  the  specifica- 
tions. All  these  tests  were  made  from  the  same  sample  of  cement, 
using  the  same  sand,  mixed  and  molded  in  the  same  laboratory,  and 
broken  by  the  same  machine.  The  writer  knew  that  the  "  personal 
equation  "  was  a  more  or  less  important  factor  in  all  testing,  but  had 
no  idea  of  its  great  magnitude  in  cement  testing. 

To  find  what  varying  results  different  persons  would  obtain 
from  the  same  sample  of  cement,  the  writer  had  ten  samples  taken 
from  as  many  barrels  of  a  certain  brand  of  Portland  cement.  These 
samples  were  thoroughly  mixed  together  and  portioned  into  ten 
smaller  samples  of  average  quality,  which  were  sent  to  ten  different 
persons,  with  a  request  that  a  seven-day  tensile  test,  one  to  three 
sand,  be  made  according  to  their  understanding  of  the  method  pro- 
posed by  the  Committee  of  American  Society  of  Civil  Engineers. 
The  accompanying  table  gives  the  results  obtained  from  nine  differ- 
ent persons  arranged  according  to  their  averages. 

What  value  has  a  tensile  requirement  in  cement  specifications 
under  the  present  method  of  testing  when  one  person  obtains  30  Ibs. 
and  another  100  Ibs.  as  a  result  upon  the  same  sample  ?  The  cement 
which  one  engineer  would  accept  would  be  rejected  by  another  under 
the  same  specifications.  Where  do  the  contractor  and  cement  manu- 
facturer stand  in  this  matter  ?  The  writer  knows  that  cement  can  be 
made  to  stand  almost  any  tensile  requirement  within  reasonable  limits 
that  would  ordinarily  be  made  by  varying  the  method  of  mixing  and 
molding,  but  when  the  mixing  and  molding  are  supposed  to  be  done 
in  accordance  with  a  given  method  and  yet  the  results  vary  widely, 
either  the  method  is  at  fault  or  the  results  have  no  value  unless 
weighed  by  the  varying  personal  equation  of  the  manipulator. 


166 


AMERICAN   CEMENTS. 


AMERICAN    CEMENTS.  167 

It  may  be  said  that  when  an  engineer  prepares  his  specifications 
for  cement,  he  knows  how  much  he  can  obtain  from  a  good  cement 
in  the  way  of  tensile  strength.  If  this  is  the  case  he  certainly  must 
have  had  one  or  more  brands  in  mind  at  the  time  of  writing  the 
specifications.  Then  why  not  specify  the  brands,  stating  chemical 
limits,  time  of  setting,  specific  gravity,  etc.  ?  The  objection  to  this 
method  is  that  a  given  brand  of  cement  will  vary  in  tensile  strength. 
Does  any  one  suppose,  however,  that  a  well-established  brand  will 
drop  much  over  70  per  cent,  from  the  requirements  that  an  engineer 
would  ordinarily  specify  ?  According  to  the  accompanying  table  the 
brand  could  drop  that  amount  before  it  would  be  rejected  by  some 
other  engineer  under  the  same  specifications. 

The  writer  had  two  men  in  his  employ,  both  equally  skilled  in 
cement  testing,  make  a  tensile  test  on  five  briquettes,  one  to  three  sand, 
on  the  same  sample  of  cement.  The  tests  were  made  in  the  same 
laboratory,  the  mixing  and  molding  being  done  at  the  same  time  and 
the  same  bath  was  used,  thus  eliminating  all  atmospheric  and  water 
conditions.  The  results  were  to  each  other  as  85  to  100;  and  if  the 
lower  one  had  been  taken  the  cement  would  have  fallen  below 
requirements,  while  taking  the  higher  result,  the  cement  would  have 
passed.  The  question  was,  which  result  to  adopt  ?  Again,  two  men 
employed  by  the  same  cement  manufacturers,  and  accustomed  to 
making  cement  tests  for  their  employers,  made  five  briquettes  each 
from  the  same  sample  of  cement.  The  briquettes  were  broken  by 
the  same  machine  and  operator  with  results  standing  as  58  to  100. 
All  of  the  before-mentioned  tests  were  made  upon  a  sand  mixture  of 
three  to  one,  and  it  might  be  said  that  if  neat  tests  had  been  made 
closer  results  would  have  been  obtained.  This  brings  up  the  question 
as  to  the  relative  value  of  sand  tests  vs.  neat  tests,  in  which  the 
writer  favors  the  former,  as  they  conform  more  nearly  to  practise.  A 
given  person  skilled  in  cement  testing  can  obtain  results  from  the 
same  sample  of  cement  under  normal  conditions  using  the  present 
method  of  testing  within  5  per  cent,  of  the  mean  value. 

The  writer  knows  a  cement  inspector  in  one  of  the  larger  cities 
who  is  frequently  compelled  to  go  out  on  work,  take  a  large  number 
of  samples,  return  to  his  laboratory  with  possibly  25  to  30  Ibs.  of 
cement,  and  then  go  to  work  and  make  one  hundred  briquettes. 
Does  any  one  suppose  the  last  briquette  made  received  the  same 


168 


AMERICAN    CEMENTS. 


AMERICAN    CEMENTS. 


169 


200 


140 


Hand  Machine. 

Full  Line, 
Power  Machine. 

Numbers  on  Line 
Denote  Laboratory. 


work  as  the  first  one,  or  the  first  one  the  treatment  that  would  have 
been  given  it  if   a  fewer  number  of  briquettes  had  been  required  ? 

This   is    probably  an 
extreme      case,      but, 

nevertheless,   cements 
to** Lin*  stand     Qr     fall    up(m 

this  inspector's  report. 
Accomp  a  n  y  i  n  g 
the  table  is  a  diagram 
(Fig.  I)  showing  the 
relation  between  the 
percentage  of  absorp- 
tion of  the  broken 
briquettes  and  their 
tensile  strength.  The 
relation  of  the  bri- 
quettes broken  by 
power  -  driven 
machines  is  rather 
striking.  The  term 

"  power-driven  "  is  applied  to  any  testing  machine  which  applies  the 

load  other  than  by  hand. 

Upon  examination  of  the  broken   briquettes,  all   of  which   had 

been  returned,  it  was  noticed  that  they  had  varied  greatly  in  density 

In  a  letter  accompanying  the  report  from  one  of  the  laboratories,  it 

was  stated :  — 


w 

?>9 

IP 

j.ti 

\ 

* 

> 

^ 

Yi/ 

T/ 

a.. 

\ 

"V 

No 

5. 

& 

s 

3s 

^ 

No. 

4. 

x 

X 

j-' 

V} 

No. 

6. 

\ 

No, 

2 

s 

^s^ 

<i 

No. 

/ 

Absorption  in  PftrcerrT  Average  of  Briquettes. 
(a) 

FIG.    I. 

Diagram  showing  relation  between  absorption  and  tensile 

strength  of  cement  briquettes  broken  by  automatic 

and  hand  machines. 


FIG.    2. 

Difference  in  density  of  two  cement  briquettes  of  the  same  composition  and  molded  by 
the  same  method  but  by  different  persons. 


170 


AMERICAN    CEMENTS. 


^Diatfram  Short/ntf  Relation  he  faeen  absorption 

— 

in  percent  anal  Tcnsi/eSfrcnffh  in  pounds  - 

-  porrea  Line      FULL    LINE    :  NUMBERS  o/t  LINSS 

7"c/7S//e  Strengfh  Pounds  average.  (PJ  

Z5O 

N* 

d 

2.40 

3 

£7VO 

iZO 

*-!" 

e 

2IO 

\ 

^ 

ZOO 

\ 

190 

\ 

IBO 

N' 

7 

\ 

170 

^ 

\ 

\ 

160 

"S 

"x 

1?6 

\ 

15O 

N 

N* 

5 

> 

LAD 

\ 
A 

v 

i 

i^n 

V 

^N*"* 

4- 

I3.O 

X!'^ 

s^ 

HO 

<*> 

^ 

N> 

5 

I  OO 

N 

N? 

[ 

90 

\ 

\, 

9° 

\ 

TO 

4 

«* 

I 

7              8              9              10             II              IZ             13 

ffbsorptioi*  in  percent  averarfc  of  br/pueties.  i 

'SL 

AMERICAN    CEMENTS.  171 

The  quartz  grains  are  so  nearly  of  one  size  that  the  volume  of  voids 
left  to  be  filled  by  the  cement  is  excessive.  If  the  sand  (or  quartz)  were  of 
graduated  sizes  the  cement  would  be  used  wholly  for  coating  the  grains 
and  not  for  filling  relatively  larger  voids.  In  this  case  the  broken  bri- 
quettes show  clearly  that  the  cement  was  quite  insufficient  to  fill  the  voids, 
as  the  briquettes  are  quite  open  and  porous. 

The  briquettes  mentioned  were  extremely  porous,  while  others 
were  quite  dense. 

Fig.  2,  reproduced  directly  from  a  photograph  showing  a  very 
dense  and  a  very  porous  briquette,  illustrates  the  point  brought  out 
above  quite  clearly.  The  most  porous  briquette  is  shown  at  the 
right,  and  is  from  laboratory  No.  i.  The  left-hand  briquette  is  from 
laboratory  No.  7. 

The  percentage  of  absorption  of  the  broken  briquettes  was 
assumed  as  a  measure  of  their  density,  and  was  obtained  by  allowing 
the  briquettes  to  remain  in  a  dry  room  for  two  weeks  or  more,  then 
placing  them  in  an  oven  having  a  temperature  of  100  degs.  C. 
They  were  taken  out  of  the  oven  at  the  end  of  two  hours  and  care- 
fully weighed,  then  placed  in  water  for  48  hours,  removed  and  again 
carefully  weighed.  The  absorption  was  computed  in  per  cent,  of  the 
original  weight  and  averaged. 

The  tensile  strength  of  the  briquettes  broken  by  power-driven 
machines,  with  one  exception,  follows  very  closely  P  =  280  —  14.3  a, 
where  P  is  the  tensile  strength  in  pounds  and  a  the  percentage  of 
absorption,  obtained  as  above  stated.  From  this  relation,  it  would 
seem,  if  percentage  of  absorption  is  any  measure  of  density,  that  the 
mortar  for  these  briquettes  received  about  the  same  mixing,  and  that 
the  variance  in  tensile  strength  is  due  to  the  molding  alone.  While 
this  may  be  true  for  the  briquettes  in  question,  the  writer  does  not 
believe  it  true  in  general,  as  the  mixing  of  mortar  for  briquettes  is 
too  important  a  factor  to  be  decided  one  way  or  another  by  so  few 
comparisons. 

The  percentage  of  water  used  by  the  different  manipulators  in 
making  the  briquettes  varied  33^  per  cent.,  due  to  the  operators' 
varying  understanding  of  the  term  "  stiff  and  plastic  "  in  connection 
with  temperature.  In  one  case  a  decrease  of  20  per  cent,  in  water 
gave  an  increase  in  tensile  strength  of  5.2  per  cent. 

Single  molds  were  decidedly  in  favor,  only  two  out  of  nine  per- 


172 


AMERICAN    CEMENTS. 


AMERICAN    CEMENTS.  173 

sons  using  gang  molds.  The  writer  believes  it  possible  to  obtain 
higher  results  from  single  than  from  gang  molds,  but  if  both  were  to 
be  treated  the  same,  the  results  would  differ  but  slightly.  A  letter 
from  one  of  the  laboratories  stated  that  results  were  about  the  same 
whichever  molds  were  used.  A  person  having  a  large  number  of 
briquettes  to  make  will  find,  without  doubt,  that  gang  molds  are 
preferable. 

The  term  "  struck  off  "  seems  to  mean  that  both  sides  of  the 
briquette  are  to  receive  that  treatment ;  at  least,  two  out  of  every 
three  operators  so  interpret  it.  There  is  not  much  doubt  but  that  a 
given  amount  of  work  distributed  equally  over  two  sides  will  give  a 
denser  briquette  than  if  one  side  only  received  the  whole  of  it. 
Working  both  sides  of  a  briquette  gives  a  more  homogeneous  cross- 
section,  which  is  as  important  as  uniformity  of  the  several  briquettes, 
particularly  when  it  is  remembered  that  the  load  in  testing  is  applied 
at  four  points. 

The  placing  of  the  briquette  in  water  flatwise  seems  to  be  the 
favored  position.  The  writer,  however,  prefers  placing  them  in 
water  on  edge,  as  more  surface  is  exposed  to  the  direct  action  of  the 
water.  The  objection  to  this  method  is  the  danger  of  the  briquette 
changing  form  under  the  action  of  its  own 'weight.  The  writer 
never  has  had  any  trouble  from  this  cause,  nor  does  he  know  of  any 
one  else  who  has  had  any. 

Still  water  for  the  bath  seems  to  be  in  almost  general  use.  This 
is  probably  due  to, the  difficulty  and  expense  of  having  running  water, 
which  no  doubt  would  be  preferred  if  a  choice  were  given.  The 
practise  of  using  the  same  still-water  bath  over  and  over  again  can- 
not be  too  strongly  condemned.  The  writer  knows  of  laboratories 
where  this  is  common  practise,  and  where  fresh  water  is  added  in 
quantities  sufficient  only  to  replace  that  lost  by  evaporation.  In 
running-water  baths,  the  supply  should  be  so  arranged  as  not  to  come 
directly  upon  the  immersed  briquettes.  This  latter  point  is  also 
often  overlooked. 

Power-driven  testing  machines  are  decidedly  in  the  majority. 
The  writer  believes  that  hand-driven  machines  should  be  entirely 
abandoned,  as  it  is  about  all  an  ordinary  mortal  can  do  to  handle 
one  crank  without  being  compelled  to  take  care  of  two.  In  power- 
driven  machines  the  writer  prefers  those  applying  the  load  by  the 


174  AMERICAN    CEMENTS. 

weight  of  water  or  shot  to  those  applying  the  load  by  means  of  a 
screw  driven  by  gearing  and  belts,  as  he  believes  the  former  to  give 
a  more  uniform  rate  of  increase.  Fig.  3  shows  the  construction  of 
the  machine  designed  by  the  writer. 

The  load  is  applied  by  water  flowing  into  a  tank  suspended  from 
the  long  arm  of  a  very  sensitive  1 5  to  i  lever.  The  weight  of  the 
lever  and  tank  is  counterbalanced  by  an  adjustable  weight  shown  on 
the  left.  Water  is  admitted  to  the  tank  from  a  large  reservoir  on  the 
roof  under  a  practically  constant  head  of  90  ft.,  so  there  is  no  sensible 
variation  of  pressure  in  the  stream  admitted  through  a  carefully  fitted 
gate  valve  in  the  supply  pipe.  The  position  of  this  valve  at  "  on," 
"  off,"  and  all  intermediate  points  is  shown  by  an  index  attached  to 
the  stem  of  the  valve  and  registering  on  a  dial  marked  off  with  the 
number  of  pounds  per  minute  applied  to  the  specimen  as  determined 
and  verified  by  previous  experiment. 

When  the  briquettes  break  the  lever  drops  a  few  inches,  then  the 
plunger  at  the  right  end  of  the  lever  enters  the  pneumatic  stop,  and 
the  lever  and  tank  are  gradually  brought  to  rest.  During  the  fall  of 
the  tank  and  before  it  comes  to  rest,  a  chain  attached  to  the  end 
of  the  valve  stem  in  the  tank  is  brought  into  tension  and  arrests  the 
descent  of  the  valve  before  its  seat  stops  descending.  The  opening 
of  this  valve  allows  the  contents  of  the  tank  to  be  quickly  discharged 
into  a  hopper  placed  upon  the  floor,  and  is  then  carried  off  through 
a  waste  pipe  to  the  sewer.  As  soon  as  the  tank  has  discharged  its 
contents,  the  weight  on  the  left  end  of  the  lever  brings  the  lever  and 
tank  into  the  position  shown  in  the  illustration,  the  valve  taking  its 
seat  during  this  movement  and  the  machine  is  ready  for  another 
break.  The  actual  load  can  be  applied  at  from  o  to  80  Ibs.  per 
minute,  thus  giving  an  increase  of  stress  of  from  o  to  1,200  Ibs.  per 
minute.  The  speed  generally  used  is  400  Ibs.  per  minute,  and  with 
the  valve  set  for  this  speed  the  needle  beam  will  float  every  time 
within  \  second  of  the  proper  time. 

The  stress  on  the  specimen  is  measured  by  a  poise  traveling  on 
a  graduated  scale  beam,  which  can  be  read  by  means  of  a  vernier  to 
i  Ib.  and  can  be  moved  automatically  or  by  hand  at  the  wish  of  the 
operator.  The  automatic  movement  is  accomplished  by  the  following 
described  device :  — 

The  horizontal  disk  and  its  engaged  friction  wheel  are  driven 


AMERICAN    CEMENTS.  175 

continuously  by  the  pulley  placed  at  the  lower  end  of  the  vertical 
shaft  and  belted  to  overhead  shafting.  This  friction  wheel  is  feath- 
ered to  a  sleeve  that  runs  loose  on  its  shaft  and  carries  a  coned 
clutch  that  is  nominally  disengaged  from  its  cone,  which  is  also 
feathered  to  the  shaft,  and  can  be  moved  slightly  longitudinally  on 
the  shaft  into  contact  with  the  clutch  by  the  action  of  the  vertical 
lever. 

When  the  needle  beam  rises,  it  makes  contact  through  a  verti- 
cal pin  in  the  top  of  the  frame,  which  completes  an  electric  circuit 
and  sends  a  current  through  the  electro-magnet  and  causes  it  to 
attract  its  armature  at  the  lower  end  of  the  vertical  lever,  which, 
moving  to  the  right,  engages  the  friction  clutch  and  causes  the  shaft 
to  revolve.  This  shaft  operates  the  sprocket  wheel  and  chain,  which 
draw  out  the  poise  on  the  scale  beam  until  the  needle  beam  drops, 
breaking  the  electric  circuit.  Breaking  the  electric  circuit  releases 
the  armature  and  allows  the  friction  clutch  to  disengage  and  the 
poise  comes  to  rest.  The  friction  wheel  may  be  set  at  a  greater  or 
less  distance  from  the  center  of  the  disk  by  turning  the  capstan  head 
nut,  and  the  chain  is  overhauled  faster  or  slower,  causing  the  poise 
to  move  accordingly.  If  desired,  the  poise  may  be  operated  by  the 
hand  wheel  without  interfering  with  the  automatic  device  other  than 
cutting  out  the  circuit.  The  chain  is  attached  to  the  poise  in  line 
with  the  three  knife-edges  of  the  scale  beam,  hence  the  tension  in 
the  chain  has  no  tendency  to  lift  up  or  pull  down  the  poise.  This 
point  is  often  overlooked  in  designing  this  detail,  not  only  in  cement 
machines  but  in  testing  machines  in  general.  The  writer  has  a 
cement  machine  in  which  the  error  due  to  this  cause  is  over  15  Ibs. 

This  machine,  as  described,  has  been  in  almost  constant  use  for 
eighteen  months  and  has  given  entire  satisfaction.  The  operator 
has  simply  to  place  the  briquette  in  the  clips,  open  the  supply  valve, 
wait  until  the  briquette  breaks,  and  then  note  the  reading  on  the 
scale  beam.  The  objection  to  this  machine  is  the  space  it  occupies, 
requiring  a  floor  area  of  7  by  2  ft.,  and  the  necessity  of  a  constant 
head  of  water. 

From  the  figures  given  in  the  table  it  is  evident  that  the  per- 
sonal equation  is  a  decidedly  important  factor  in  cement  testing,  and 
before  tensile  requirements  in  specifications  can  have  any  meaning, 
a  method  must  be  adopted  that  will  considerably  reduce  or  entirely 


176  AMERICAN   CEMENTS. 

eliminate  this  factor.     With  this  in  view,  the  following  requirements 
are  suggested :  — 

1.  Mixing  and  tempering  by  machinery,  using  enough  mixture 
to  make  a  given  number  of  briquettes. 

2.  Molding  under  a  given  pressure. 

3.  Regulation  in  regard  to  the  bath  and  manner  of  placing 
briquettes  in  the  same. 

4.  Abolishing  the  use  of  all  testing  machines  applying  the  load 
by  hand. 


THE  FAIRBANKS  CEMENT  TESTING  MACHINE. 

The  great  necessity  and  importance  that  all  cement  used  in  any 
given  work  should  be  of  a  uniform  quality  and  strength  are  facts 
well  understood  by  all  contractors  and  builders. 

It  was  not,  however,  until  the  introduction  of  the  Fairbanks 
Testing  Machine,  some  twelve  years  ago,  that  it  became  an  easy 
and  convenient  matter  to  quickly  and  accurately  test  any  sample  of 
cement  required,  the  machine  being  automatic  in  its  operation,  and 
so  compact  that  it  may  be  placed  on  a  small  table,  or  shelf,  in  any 
office.  In  the  machine  as  shown  in  the  accompanying  illustration 
are  embodied  some  recent  patents,  the  most  important  of  which  are 
the  adjustable  clamps,  N.  N.,  hung  on  steel  points  and  ball  bearings. 
Their  bearing  surfaces  are  free  to  adjust  themselves  quickly  and 
accurately  in  any  direction  to  the  slight  inequalities  of  the  briquette, 
without  any  lost  motion,  so  that  the  briquette,  under  tension,  will  be 
broken  fairly  in  its  smallest  section. 

In  the  illustration  S.  represents  the  mold  in  which  the  sample 
briquette  is  made,  the  mold  being  laid  on  a  smooth  board  or  glass 
plate  and  filled  with  mixed  cement,  when  the  top  is  struck  off  even 
with  the  top  of  the  mold.  After  the  cement  has  set  sufficiently,  the 
fastenings  at  the  ends  are  loosened,  and  the  mold  is  carefully  taken 
away  from  the  specimen.  To  make  the  test,  the  cup,  F.,  is  hung  on 
the  beam,  D.,  as  shown ;  the  poise  R.,  placed  at  the  zero  mark ;  the 
beam  balanced  by  turning  the  ball,  L.,  and  a  hopper,.  B.,  at  the  top, 
filled  with  fine  shot.  The  molded  sample  of  cement,  U.,  is  then 
placed  in  the  clamps,  and  the  hand-wheel,  P.,  is  adjusted,  so  that  the 


AMERICAN    CEMENTS. 


177 


graduated  beam,  D.,  rises  nearly  to  the  stop  K.  A  valve,  J.,  is  then 
opened  to  allow  the  shot  to  run  into  the  cup,  F.,  through  the  pipe, 
I.,  the  shot  continuing  to  run  until  the  specimen  is  broken  by  the 
drawing  down  of  the  graduated  beam,  when  the  flow  is  automati- 
cally cut  off  by  the  valve.  The  valve  itself  forms  one  of  the  recent 
improvements  of  the  machine,  as  it  may  be  adjusted  to  permit  of  a 
larger  or  a  smaller  flow  of  shot,  and  the  point  of  cut-off  is  arranged 


THE   FAIRBANKS    CEMENT   TESTING   MACHINE. 

at  the  discharge  end  of  the  pipe,  making  the  weight  of  shot  de- 
livered to  the  cup  correspond  more  closely  to  the  movement  of  the 
beam.  After  the  specimen  is  broken,  the  cup,  F.,  is  hung  on  the 
hook  under  the  large  ball,  E.,  and  the  shot  is  weighed  in  the  regular 
way,  using  the  poise  R.,  on  the  graduated  beam,  and  the  weights 


178  AMERICAN    CEMENTS. 

H.,  on  the  counter-poise  weight,  G.,  the  result  showing  the  number 
of  pounds  required  to  break  the  specimen. 

The  briquette  molds  form  the  samples  to  be  tested  of  the  exact 
size  and  dimensions  called  for  by  the  American  Society  of  Civil  En- 
gineers, having  i  sq.  in.  as  their  smallest  section.  The  briquettes 
are  about  2  ins.  wide  at  each  end,  and,  with  very  slightly  round- 
ing outer  surfaces,  taper  inward  toward  the  middle,  with  a  form 
admirably  adapted  to  be  firmly  engaged  by  the  clamps  without  the 
binding  of  the  latter  on  any  special  line.  The  improved  clamps 
hold  the  briquettes  in  a  manner  superior  to  cushioned  clamps, 
and  the  action  of  the  machine  is  strictly  automatic  while  the  test 
is  being  made,  there  being  no  parts  of  the  machine  to  be  moved, 
thereby  avoiding  danger  from  sudden  jarring,  which  might  break 
the  sample  before  reaching  the  limit  of  its  strength.  The  ma- 
chines have  no  springs  or  hydraulic  appliances  to  get  out  of 
order,  but  are  constructed  with  levers,  steel  pivots,  and  bearings 
strictly  on  the  principle  of  the  most  improved  weighing  apparatus. 
The  Fairbanks  Company  make  machines  in  two  sizes,  one  to  test 
up  to  600  Ibs.,  and  the  one  shown  in  our  illustration,  in  which  tests 
are  made  up  to  1 ,000  Ibs.  A  mold  is  furnished  with  each  machine. 


THE    RIEHLE    U.    S.    STANDARD  CEMENT  TESTING 
MACHINE. 

The  cement  tester  represented  is  one  of  1,000  Ibs.  capacity. 
It  resembles,  in  many  respects,  a  similar  type  machine  of  2,000  Ibs. 
capacity.  The  general  appearance  is  the  same,  but  the  beam  and 
corresponding  parts  of  the  larger  capacity  machine  are  heavier  and 
slightly  larger.  The  extreme  length  of  this  machine  is  6  ft.  2>£  ins. ; 
extreme  height,  5  ft.;  extreme  width,  2  ft.  The  1,000  Ib.  machine 
is  capable  of  testing  cement  briquettes  with  reduced  section  of  I  in. 
area.  The  molds  are  adapted  to  the  A.  S.  C.  E.  standard.  All  the 
weight  of  this  machine  is  on  one  beam.  The  poise  is  propelled 
the  entire  length  of  beam  by  a  hand  wheel  shown  at  the  extreme 
left  —  at  the  butt  end  of  the  beam.  The  power  is  applied  by  a 
crank,  worm,  and  gear,  shown  to  the  extreme  left  of  the  machine. 
The  specimen  being  in  position,  the  power  being  applied,  the  beam 


AMERICAN    CEMENTS. 


179 


raises,  and  the  indicator  point  shown  also  at  the  extreme  left  of  the 
machine  at  upper  part,  falls.  The  experimenter  can  operate  the  ma- 
chine with  his  left  hand  on  the  crank,  and  his  right  propelling  the 
poise.  After  a  little  practise,  the  operator  can  become  sufficiently 


THE    RIEHLE    UNITED    STATES    STANDARD    CEMENT    TESTING 
MACHINE. 

expert  to  keep  the  beam  in  exact  equipoise.  The  top  indicating 
beam  is  about  on  a  level  with  the  eye  of  the  operator,  and  he  can 
quickly  see  whether  the  strain  applied  to  specimen,  and  the  weigh- 
ing of  the  same  are  progressing  in  harmony. 

This  machine  was  designed  after  a  thorough  examination  of 
the  most  approved  forms  of  cement  testers  in  use  in  this  country 
and  in  Europe,  with  additions  and  improvements  introduced  by  us 
to  suit  the  requirements  of  American  engineers  and  manufacturers. 


UNIVERSITY 
OF  «. k,\ 


180  AMERICAN   CEMENTS. 

The  marks  on  the  beam  run  up  to  the  full  capacity  without  having 
to  move  the  poise  back  and  add  additional  weights. 

To  make  the  machine  more  compact  than  the  standard  necessi- 
tates the  use  of  a  complication  of  leverage,  which  tends  to  effect  the 
accuracy  of  the  machine.  All  appliances  of  this  kind  have  been 
studiously  avoided  by  us,  as  the  nature  of  the  material  to  be  tested 
does  not  admit  of  a  sacrifice  of  accuracy  to  possible  convenience. 
This  machine  is  not  automatic,  but  responds  to  every  call  made 
upon  it  up  to  full  capacity,  with  an  accuracy  that  does  not  admit  of 
adverse  criticism.  The  arrangement  of  the  grips  on  this  machine, 
"  swinging  them  on  pin  points,"  is  used  only  on  this  machine,  and 
requires  no  explanation  or  comments,  as  the  advantages  are  perfectly 
apparent  to  any  one  who  knows  the  inaccurate  results  consequent 
upon  gripping  a  briquette  of  cement  otherwise  than  on  a  "  dead 
straight  line,"  which  is  impossible  with  "  pin  point  grips." 

This  machine  can  be  arranged  to  make  crushing  tests,  but  we 
do  not  recommend  the  1,000  Ib.  machine  for  that  purpose,  as  it 
is  not  heavy  enough.  By  proper  appliances  one  can  make  trans- 
verse tests,  also  torsional  tests.  These  latter  tests  have  not  been 
receiving  as  much  attention  as  the  former,  but  are  now  demand- 
ing attention,  and  will  shortly  be  universally  considered  and  required. 


THE    CUMMINGS    HYDROSTATIC    CEMENT 
TESTING  MACHINE. 

The  Cummings  Hydrostatic  Cement  Testing  Machine  was  de- 
vised by  the  author,  and  is  represented  in  two  styles  of  construction. 

The  vertical  machine  is  provided  with  two  pistons,  while  the 
horizontal  machine  contains  but  one. 

It  is  evident  that  the  capacity  of  these  machines  is  governed 
by  the  area  of  the  piston  or  pistons  which  impel  the  movable  jaw  or 
clamp. 

The  dimensions  of  the  vertical  machine  are:  Length,  6  ins.; 
breadth,  4^  ins.,  and  height,  6  ins.  Capacity,  300  Ibs.  Total 
weight,  13  Ibs. 

The  dimensions  of  the  horizontal  machine  are  :  Length,  9^ 
ins.;  breadth,  4^  ins.,  and  height,  4^  ins.  Capacity,  1,500  Ibs. 
Total  weight,  20  Ibs. 


AMERICAN    CEMENTS. 


181 


These  machines  are  nickel  plated,  and  are  an  ornament  in  any 
office. 

The  liquid  used  in  these  machines  is  glycerin,  which  insures 
against  injury  by  exposure  in  freezing  weather. 

The  hights  given  are  exclusive  of  the  gages. 

The  pressure  on  the  pistons  is  produced  by  turning  the  crank, 


CUMMINGS  HYDROSTATIC    CEMENT   TESTER,    CAPACITY    300   POUNDS. 

which  is  attached  to  a  screw-threaded  stem,  to  which  is  attached  a 
piston  of  smaller  area  than  those  which  impel  the  movable  jaw. 

The  pressure  is  registered  by  a  gage,  the  accuracy  of  the 
latter  being  confirmed  by  a  column  of  mercury. 

The  stem  of  the  gage  is  provided  with  a  valve  which  prevents 


182 


AMERICAN    CEMENTS. 


a  too  rapid  return  of  the  indicator  hand  to  zero  upon  release  of  the 
breaking  strain,  and  each  gage  has  a  maximum  registering  hand. 

The  strain  applied  in  the  breaking  of  the  briquettes  is  exactly 
at  right  angles  to  the  one- inch  cross  section. 

This  is  an  important  feature,  as  usually  the  direction  of  the 
breaking  strain  is  left  to  accidental  adjustment  in  the  machines  hav- 
ing the  jaws  or  clamps  secured  by  links. 

A  briquette  which,  by  reason  of  its  having  been  removed  from 
the  mold  before  it  has  hardened  sufficiently  to  maintain  its  perfect 
shape,  cannot  be  accurately  tested  in  any  known  testing  machine, 


CUMMINGS  HYDROSTATIC  CEMENT  TESTER,  CAPACITY    I,5OO  POUNDS. 

whether  the  jaws  be  rigid  or  held  by  links  or  points,  and  such  bri- 
quettes should  always  be  rejected. 

The  supposition  that  in  the  construction  of  the  hydrostatic 
testing  machines  they  would  be  subject  to  a  certain  amount  of  fric- 
tion, due  to  the  contact  of  the  pistons  on  the  inner  surfaces  of  the 
cylinders,  for  which  allowance  would  have  to  be  made,  was  disproved 
in  actual  practise,  by  the  breakings  of  many  thousands  of  briquettes, 


AMERICAN   CEMENTS.  183 

made  from  the  same  cement,  by  the  same  person,  in  the  same  room, 
and  running  through  a  term  of  years. 

The  briquettes  were  broken  alternately  on  the  Fairbanks,  the 
Riehle  and  the  Cummings  machines,  and  the  variation  in  average 
results  was  surprisingly  slight,  proving  conclusively  that  the  factor 
of  friction  could  not  obtain,  as  there  could  be  no  friction  without 
motion,  and  no  motion  is  possible  until  after  the  fracture  of  the  bri- 
quette. 

At  all  events,  the  records  of  breakings  showed  no  higher  re- 
sults for  the  hydrostatic  machines  than  for  either  of  the  other  two 
machines  named.  * 


Although  the  utilization  of  natural  cement  rock  for  Portland  pur- 
poses is  not  practised  to  any  great  extent  in  Europe,  owing,  no  doubt, 
to  the  uneven  quality  of  such  rocks,  yet  in  this  country  more  than 
two  thirds  of  the  Portland  cement  produced  is  from  this  source. 

Limestone  to  the  extent  of  10  to  15  per  cent,  is  added  to  the 
cement  rock,  which,  in  the  section  where  such  Portlands  are  manu- 
factured, contains  an  excess  of  clay. 

Portland  cements  produced  in  this  manner  are  fully  equal  in 
quality  to  those  which  are  compounded  by  an  artificial  admixture  of 
clay  and  carbonate  of  lime,  and  it  may  be  said,  in  passing,  that  there 
are  no  Portland  cements  in  the  world  superior  to  those  produced  in 
this  country. 

The  consumer  who  uses  imported  brands  in  preference  does  so 
at  his  own  risk,  for  no  manufacturer  in  Europe  guarantees  the  quality 
of  his  cement  after  it  is  delivered  into  this  country.  The  Portland 
producers  here  guarantee  their  product,  as  do  the  Rock  cement  manu- 
facturers, and  they  are  here  on  the  ground  ready  at  all  times  to  make 
good  any  damage  which  may  be  caused  by  the  failure  of  their  cements. 

And  yet,  at  the  present  time,  there  are  three  barrels  of  imported 
Portland  used  in  this  country  to  one  of  our  home  production.  Such 
is  prejudice.  Still,  it  is  pleasing  to  note  that  it  is  gradually  dying 
out,  and  it  is  to  be  hoped  that  the  time  is  not  far  distant  when 
American  Portlands  will  be  used  in  preference  to  those  from  other 
countries. 

*  The  foregoing  descriptions  of  cement  testing  machines  were  prepared  by  those  who 
control  the  respective  inventions. 


184 


AMERICAN    CEMENTS. 


If  we  take  a  few  pounds  of  correctly  proportioned  cement  rock 
in  one  piece,  and  divide  it  into  two  equal  parts,  and  designate  them 
as  samples  No.  I  and  No.  2,  and  take  No.  I  and  calcine  it,  and  then 
grind  it  to  powder,  we  have  converted  it  into  a  natural  hydraulic  cement. 

If  we  take  sample  No.  2  and  first  grind  it  to  powder,  and  then 
calcine  it,  and  again  reduce  it  to  powder,  we  have  converted  it  into  a 
Portland  cement.  This  comprises  all  the  difference  in  the  manufac- 
ture of  the  Rock  and  Portland  cements. 

Now  if  we  mold  these  samples  separately  into  briquettes  and 
submit  them  to  a  tensile  strain  test  per  square  inch  of  cross  section, 
treating  them  alike  as  to  time  in  air  and  in  water,  it  is  probable  that 
when  tabulated  they  would  appear  about  as  shown  in  the  following 
table,  provided,  of  course,  that  both  samples  had  been  calcined  in 
accordance  with  the  methods  now  in  vogue  by  the  manufacturers  of 
each  class. 

TABLE  A. 


Time. 

Lbs. 
i  Day. 

Lbs. 
i  Week. 

Lbs. 
i  Month. 

Lbs. 
6  Months. 

Lbs. 
i  Year. 

No.  i 

65 

"5 

'75 

350 

500 

No.  2 

"5 

400 

500 

75° 

J,000 

Granting  that  this  table  is  approximately  correct,  and  we  have 
a  large  collection  of  tables  gathered  from  many  sources  which  sub- 
stantially verify  the  figures  given,  what  are  the  conclusions  to  be 
drawn  therefrom  ? 

If  the  actual  values  are  to  be  measured  by  the  pounds  in  tensile 
strength  which  the  briquettes  are  capable  of  sustaining,  and  this  is 
the  prevailing  belief  at  the  present  time,  and  has  prevailed  during  the 
past  thirty-five  years,  it  would  seem  indisputable  that  up  to  one 
year  No.  i  had  but  one  half  the  value  of  No.  2. 

It  is  safe  to  assert  that  not  one  engineer  or  architect  in  a  thou- 
sand carries  his  tests  beyond  one  year. 

It  is  equally  safe  to  assert  that  not  one  in  a  hundred  carries  tests 
beyond  three  months. 

It  is  not  difficult  then  to  understand,  in  the  light  of  the  table 
given,  how  the  prevailing  opinion  became  so  firmly  established. 


AMERICAN    CEMENTS.  185 

The  idea  that  the  higher  the  test  the  greater  the  value  has  come 
to  be  firmly  fixed  in  the  public  opinion  as  being  sound  beyond  question. 

The  manufacturer  whose  cement  tests  higher  than  that  of  his 
neighbor  in  a  one  or  thirty  day  test,  wears  an  air  of  superiority  which 
is  simply  indescribable. 

It  is  settled  in  his  mind  that  his  cement  is  better  than  that  of 
his  neighbor. 

And  the  neighbor  who  is  defeated  in  the  test  is  correspondingly 
depressed.  He  has  a  feeling  akin  to  that  of  the  speculator  in 
Buffalo,  N.  Y.,  who  walked  across  the  road  to  bestow  a  kick  on  a  cer- 
tain sleeping  omniverous  mammal  lying  in  the  gutter,  because  pork 
had  taken  a  drop  in  the  market  that  day. 

And  well  may  the  defeated  cement  maker  feel  somewhat  de- 
pressed, for  the  chances  are  ten  to  one  that  the  engineer  who  made 
the  tests  believes  the  higher  testing  brand  the  better  of  the  two. 

It  does  not  follow  that  the  lower  testing  cement  is  the  better, 
although  it  is  not  impossible,  by  any  means.  Neither  does  it  follow 
that  the  same  results  would  obtain  had  some  other  engineer  tested 
the  same  brands  from  the  same  packages. 

But  in  the  table  we  have  another  problem  to  deal  with.  Here 
the  two  classes  are  made  from  identically  the  same  material,  and  the 
differences  in  the  testing  can  only  be  attributable  to  the  different 
modes  of  manufacture. 

The  Portland  cement  has  set  much  more  rapidly  than  the  other 
during  the  first  year,  and  it  is  this  fact  alone  that  has  brought  almost, 
if  not  quite,  all  the  cement-making  and  cement-using  world  to  believe 
that  Portland  cement  is  vastly  superior  to  the  Rock  cement. 

The  question  arises  as  to  whether  or  not  the  prevailing  opinion 
is  founded  on  fact.  If  the  answer  is  confined  to  the  one  year's 
showing,  then  it  must  be  said  that  the  opinion  is  sound. 

But  if  the  public  could  be  brought  to  realize  that  one  year  is  but 
the  beginning  of  the  test,  that  the  real  trial  is  but  fairly  started,  and 
is  on,  so  long  as  the  work  endures  in  which  the  cement  is  used;  if 
it  were  understood  that  after  five  years  not  one  engineer  in  a  hundred 
can  tell  either  by  simply  looking  at  a  wall  laid  in  cement,  or  by  the 
use  of  the  hammer,  whether  the  cement  used  was  Rock  or  Portland 
cement,  and  if  it  were  known  that  it  is  a  fact,  that  when  we  have 


186 


AMERICAN    CEMENTS. 


occasion  to  blast  out  old  concrete  laid  in  Rock  cement  twenty-five 
years  before,  we  find  it  as  hard  as  any  rock  ;  and  if  it  were  possible 
for  the  public  to  become  as  familiar  with  three  to  five  year  tests  as 
they  are  with  the  prevailing  tests,  then  there  would  be  a  remarkable 
overturning  of  preconceived  notions  in  regard  to  cement  values,  and 
thinking  men  would  undertake  a  readjustment  of  their  opinions,  for 
nothing  is  more  certain  than  that  if  the  samples  Nos.  I  and  2  of  the 
table  given  were  carried  along  in  the  tests  yearly  from  one  year  to 
five,  the  table  A  continued,  would  appear  substantially  as  follows:  — 


TABLE  B. 


Time. 

2  Years. 

3  Years. 

4  Years. 

S  Years. 

No.  i 
No.  2 

700 
1,000 

800 
800 

900 
75° 

1,000 

600 

The  following  table  of  tests  was  made  by  C.  E.  Richards,  cement 
tester  on  the  new  Croton  Aqueduct  at  Brewster,  N.  Y.,  from  American 
Rock  cement  manufactured  by  the  author. 

Briquettes  one  square  inch  in  cross  section,  one  hour  in  air, 
balance  of  time  in  water. 


No.  of 
Briquette. 

Time  when  Made. 

Time  when  Broken. 

Tensile  Strength  Ibs. 

i 

2 

3 
4 

i 

Oct.    4,  1886. 
Oct.  ii,  1886. 
Oct.  n,  1886. 
Nov.  29,  1886. 
Nov.  21,  1886. 
Nov.  30,  1886. 

Nov.     8,  1889. 
Nov.     8,  1889. 
Nov.     8,  1889. 
Nov.     8,  1889. 

910 
860 
960 
960 

Nov.    8,1889.     Unbroken  at  i,  ooo  pounds. 
Nov.    8,1889.     Unbroken  at  i,  ooo  pounds. 

The  Richie"  1,000  pound  testing  machine  used. 

The  following  is  an  extract  from  "  Records  of  Tests  of  Cement," 
made  for  the  Boston  Main  Drainage  Works,  1878-1884,  by  Eliot  C. 
Clarke,  M.  Am.  Soc.  C.  E.,  page  160:  — 

"  The  following  series  of  tests  may  be  of  interest  on  account  of 
the  age  of  the  specimens.  The  mortars  were  made  with  an  English 
Portland  cement,  both  unsifted  as  taken  from  the  cask,  and  also 
after  it  had  been  sifted  through  the  No.  1 20  sieve,  by  which  process 
about  35  per  cent,  of  coarse  particles  were  eliminated. 


AMERICAN    CEMENTS. 


187 


TABLE  NO.  12. 

BRIQUETTES    I    SQUARE   INCH    CROSS    SECTION. 


Kind  of  Cement. 

Neat  Cement. 

Cement  i.      Sand  2. 

Cement  i.      Sand  5. 

Ordinary  cement  unsifted. 

2  Years. 

4  Years. 

2  Years. 

4  Years. 

2  Years. 

4  Years. 

603 

387 

339 

493 

182 

202 

Cement  which  passed  No. 
120  sieve. 

374 

211 

478 

5»o 

250      |        284 

"  This  table  also  shows  that  fine  cements  do  not  give  as  high 
results,  tested  neat,  as  do  cements  containing  coarse  particles,  even 
coarse  particles  of  sand.  It  also  shows  (what  is  often  noticed)  that 
neat  cements  become  brittle  with  age,  and  are  apt  to  fly  into  pieces 
under  comparatively  light  loads." 

It  cannot  be  denied  that  at  five  years  artificial  cements  are  ex- 
tremely brittle,  and  briquettes  made  from  this  class  of  cements,  if 
let  fall  on  a  stone  floor,  after  they  are  four  or  five  years  old,  will 
fly  into  as  many  pieces  as  would  a  glass  bottle  falling  from  the  same 
hight,  and  this  is  not  true  of  the  better  quality  of  Rock  cements. 

But  engineers  tell  us  that  they  cannot  wait  five  years,  or  five 
months  even,  to  learn  whether  a  cement  is  good  or  bad,  which  is  true 
enough,  but  does  not  alter  the  facts  in  the  case  ;  and  the  facts  are 
that  very  high  short-time  tests  are  unfailing  evidences  of  subsequent 
weakness. 

These  facts  are  demonstrated  in  every  table  wherein  the  tests 
have  been  carried  from  one  day  to  five  years,  that  has  ever  come 
under  the  observation  of  the  author. 

The  following  is  an  extract  from  a  lecture  delivered  by  the 
author  before  the  Society  of  Arts  of  the  Massachusetts  Institute  of 
Technology,  Boston,  November,  1887:  — 

"  The  testing  machine  reveals  many  curious  freaks,  and  taken 
on  the  principle  that  "  everything  is  for  the  best,"  it  may  yet  reveal 
to  us  that  a  cement  may  test  too  high,  that  this  modern  demand  for 
high-testing  cement,  and  the  tremendous  struggle  on  the  part  of  the 
Portland  cement  manufacturers  to  supply  it,  striving  by  every  con- 
ceivable means  to  beat  the  record,  is  all  wrong. 

"  This  may  sound  strangely  at  first,  but  a  study  of  the  tables  of 


188  AMERICAN    CEMENTS. 

long-time  tests  of  Portland  cements,  as  compiled  by  such  engineers  as 
Clarke,  of  Boston,  and  MacClay,  of  New  York,  and  others  eminent 
in  the  profession,  reveals  the  rather  startling  fact  that  briquettes  of 
neat  Portland  do  not  test  as  high  at  three  or  four  years  as  they  do  at 
one  or  two  years  old.  Clarke  says :  — 

"'They  become  brittle  with  age  and  are  apt  to  fly  into  pieces  under 
comparatively  light  loads.' 

"  If  this  is  the  result  with  neat  cement  at  that  age,  what  is  to  prevent 
the  same  results  with  sand  mixtures  at  fifteen  to  twenty  years  or  so  ? 

"The  ten  years'  tests  of  Portland  cement,  made  by  Dr. 
Michaelis,  of  Berlin,  show  that  the  maximum  strength  was  reached 
at  the  end  of  two  years,  and  this  point  held  fairly  well  until  the  end 
of  the  seventh  year ;  but  from  that  time  until  the  end  of  the  tenth 
year  there  was  a  remarkable  falling  off  in  values.  We  do  not  recol- 
lect ever  having  seen  any  table  of  long-time  tests  of  Portland  cement 
that  did  not  exhibit  similar  results,  and  it  is  more  than  probable  that 
it  may  yet  be  shown  that  our  best  natural,  slow-setting  American 
cements  may,  in  ten  to  twelve  years'  tests,  surpass  any  artificial 
cements.  The  excellent  condition  of  some  of  our  old  work,  done 
many  years  ago  with  American  cements,  would  seem  to  indicate  as 
much. 

"  At  all  events,  we  have  no  proof  that  the  Portland  is  superior 
in  the  matter  of  durability,  and  we  do  not  believe  that  clay  and  lime 
can  be  suddenly  thrown  together,  and  kept  there  by  any  skill  of  man, 
that  can,  in  any  manner,  compare  with  the  staying  qualities  as  found 
in  first-class  natural  cements,  where  the  clay  and  lime  have  existed  in 
the  most  intimate  contact  for  countless  ages." 

It  is  now  over  nine  years  since  the  foregoing  was  written,  and 
in  the  meantime  the  only  changes  in  the  views  of  the  author  on  this 
subject  have  been  to  strengthen  rather  than  to  weaken  the  proposi- 
tion then  advanced. 

Years  of  close  observation  as  to  the  changes  constantly  occur- 
ring in  a  cement  subsequent  to  its  use  in  masonry  or  concrete  leads 
to  the  inevitable  conclusion  that  a  cement  which  hardens  too  rapidly 
in  its  early  stages,  whether  it  may  be  a  natural  rock  or  an  artificial 
cement,  should  be  looked  upon  with  suspicion  rather  than  with 
approval. 


AMERICAN    CEMENTS.  189 

It  is  patent  to  every  observer  who  has  had  occasion  to  examine 
briquettes  made  from  both  classes,  and  broken  at  three  to  five  years, 
that  those  which  by  the  records  are  shown  to  have  tested  high  in 
their  early  stages  are  at  a  later  period  extremely  brittle  and  glassy, 
and  are  entirely  devoid  of  that  peculiar  toughness  which  charac- 
terizes the  slower  setting  varieties. 

A  cement  which  attains  its  limit  of  tensile  strength  rapidly  will, 
the  moment  that  limit  is  reached,  commence  to  become  brittle,  and 
from  that  time  on  there  will  be  a  continual  loss  in  cohesive  strength 
in  direct  ratio  with  its  increasing  brittleness. 

Brittleness  and  weakness  are  synonymous. 

Mr.  C.  H.  Brinsmaid,  city  cement  inspector,  City  Engineer  De- 
partment, Minneapolis,  Minn.,  has  had  twelve  years'  experience  in 
cement  testing  in  the  department  named,  and  has  compiled  some 
valuable  tables  of  tests,  some  brands  of  Portland  running  as  high  as 
nine  years. 

In  a  correspondence  with  the  author,  he  remarks  incidentally :  — 
"  Lacking  experience,  nothing  would  surprise  me  more  than  to  see 
how  very  brittle  these  old  Portland  samples  become,  and  how  they 
snap  and  fly  into  fragments  by  a  blow  of  trowel  or  hammer.  There 
is  no  question  but  that  old  Portlands  are  more  brittle  than  Rock 
cements  of  the  same  age,  however  difficult  it  may  be  to  note  the 
proper  comparison." 

In  Mr.  Brinsmaid's  tables  of  neat  Portland  tests,  the  figures 
disclose  that  three  of  the  leading  German  and  five  of  the  English 
Portlands  reach  their  limit  of  strength  at  one  year,  after  which  time 
they  begin  to  deteriorate,  at  seven  years  the  German  falling  to 
476  Ibs.,  and  the  English  to  592  Ibs. 

Referring  to  the  table  (A)  continued,  it  is  pertinent  to  repeat  the 
question,  "  What  are  the  conclusions  to  be  drawn  ?  " 

Both  No.  i  and  No.  2  are  produced  from  identically  the  same 
materials  and  in  the  same  proportions,  but  No.  I  being  a  solid  rock, 
and  No.  2  a  porous  mass,  they  are  not  affected  equally  by  the  same 
amount  of  heat,  and  it  is  from  this  cause  alone  that  one  hardens 
much  more  rapidly  than  the  other,  and  consequently  tests  higher  in 
its  early  stages.  But  that  is  no  evidence  of  superiority,  notwith- 
standing public  opinion  to  the  contrary. 

There  are  certain  classes  of  work  wherein  it  may  be  necessary 


190  AMERICAN    CEMENTS. 

to  use  the  higher  testing  varieties,  such,  for  example,  as  sidewalks  and 
similar  work,  but  for  heavy  foundations  and  massive  masonry,  to  use 
the  higher  priced  cement,  simply  because  it  tests  higher  in  short  time 
tests,  is  expensive  folly,  for  the  slower  setting  variety,  or,  in  other 
words,  the  natural  rock  cements,  have  been  successfully  used  in  the 
heaviest  masonry  in  the  world. 

It  is  well  understood  that  the  process  of  hardening  of  a  cement 
is  simply  the  crystallization  of  the  silicates,  which  commences  shortly 
after  they  have  become  hydrated  by  the  application  of  water.  Some 
hydrated  silicates  crystallize  much  more  rapidly  than  others. 

Rapid  crystallization  means  imperfect  crystallization,  uneven 
in  size,  shape,  and  texture.  In  fact,  a  mere  jumble  of  irregular 
crystals,  and  the  very  rapidity  of  their  formation  insures  subsequent 
brittleness  and  weakness,  while  those  silicates  which  crystallize 
slowly  form  crystals  perfect  in  shape,  size,  and  texture. 

Dana,  in  his  "  Manual  of  Geology,"  page  627,  in  speaking  of  the 
texture  of  rocks,  says :  "  The  grains  are  coarser  the  slower  the 
crystallization,  or,  in  other  words,  the  slower  the  rate  of  cooling 
during  crystallization ;  and  with  rapid  cooling,  they  sometimes  dis- 
appear altogether,  and  the  material  comes  out  glass  instead  of 
stone." 

So  in  the  crystallization  of  the  silicates  in  a  cement.  If  it  tests 
high  in  its  early  stages,  the  breakings  of  the  briquettes  disclose  the 
glassy  texture,  which  is  quite  unlike  the  stone-like  texture  exhibited 
in  the  slower  varieties. 

It  is  possible,  then,  that  the  testing  machine  may  yet  be  the  means 
of  convincing  the  public  that  a  cement  may  test  too  high,  as  stated 
in  the  quotation  of  nine  years  ago. 

The  author  does  not  consider  it  wild  or  extravagant  to  assert  it 
as  his  deliberate  opinion  that  the  specifications  drawn  by  the  engi- 
neer of  the  future  will  stipulate  that  the  cement  to  be  used  shall  not 
exceed  nor  fall  below  a  given  number  of  pounds  in  tensile  strength 
per  square  inch  in  cross  section  at  one,  seven,  thirty,  and  ninety  days. 

When  that  day  arrives  there  will  cease  this  unseemly  scramble 
for  high  short-time  tests.  Reason  and  common  sense  will  prevail, 
guided  by  a  practical  knowledge  of  the  chemistry  of  cements. 

It  is  not  the  purpose  of  the  author  to  disparage  or  discredit 
Portland  cements,  but  rather  to  point  out  their  defects,  in  the  hope 


OF  T^B 

f  UNIVERSITY  ) 


AMERICAN 

that  in  so  doing,  more  consideration  may  be  given  to  the  subject, 
and  juster  conclusions  reached. 

Unquestionably  an  ideal  hydraulic  cement  can  be  produced  by 
what  is  known  as  the  Portland  process,  and  there  is  but  little  doubt 
it  would  have  been  much  in  use  at  the  present  time,  had  it  not  been 
for  the  unfortunate  misinterpretation  of  the  readings  of  the  tensile 
strain-testing  machine  in  the  early  stages  of  its  existence. 

At  the  time  of  its  first  introduction  into  England,  Portland 
cements  were  selling  at  one  shilling  per  bushel,  and  rock  cements 
were  selling  at  eighteen  pence  per  bushel. 

Such  was  the  public  opinion  as  to  the  relative  values  of  the  two 
classes  of  cements  sixty-two  years  after  Parker  had  brought  out  his 
Roman  (Rock)  cement,  and  thirty-four  years  after  Aspdin  had  pro- 
duced his  artificial  (Portland)  cement. 

Even  at  the  difference  in  prices,  the  Roman  cement  had  by  far 
the  larger  share  of  the  market,  and  the  only  means  of  ascertaining 
the  relative  values  was  by  the  behavior  of  the  cements  in  actual  work, 
and  making  such  tests  as  placing  balls  of  the  cement  under  water. 

Then  came  the  tensile  strain-testing  machine,  and  it  was  soon 
ascertained  that  the  Portland  brands  tested  higher  than  the  Roman 
cements. 

It  must  have  been  an  important  event,  an  epoch,  in  fact,  in  the 
lives  of  those  engineers,  to  be  confronted  with  the  revelations  dis- 
closed by  the  testing  machine. 

They  had  been  using  both  classes  of  cements,  and  the  Rock 
cements  stood,  if  the  price  is  any  criterion,  50  per  cent,  higher  in 
their  estimation  than  the  Portland  cements.  And  yet  the  testing 
machine  showed  them  that  the  Portland  cements  were  the  stronger, 
and  so,  they  reasoned,  that  if  stronger,  they  must  be  better.  Therefore 
they  had  been  laboring  under  a  hallucination  for,  lo,  these  many  years. 

Judging  by  their  experience  in  the  use  of  both  classes,  the 
cement  which  had  seemed  to  them  to  be  the  best,  that  had  given 
them  the  least  trouble,  was  not  the  best,  after  all. 

They  never  questioned  the  soundness,  or  rather  unsoundness,  of 
their  new-found  scheme  for  determining  values. 

It  did  not  occur  to  them  that  the  higher  testing  cement  was  not 
necessarily  the  better  cement,  and  they  accepted  the  result  as  indis- 
putable. 


192  AMERICAN   CEMENTS. 

With  their  former  teachings  and  experience  on  the  one  hand, 
and  the  testing  machine  on  the  other,  the  question  was  not  long  in 
doubt.  The  machine  was  victorious,  and  thenceforward  all  judg- 
ment founded  on  experience  was  laid  aside,  and  they  became  blind 
believers  in  the  tensile  strain  tests. 

What  matter  though  they  were  continually  befogged  by  the 
frequent,  unreasonable,  and  capricious  pranks  of  the  machine,  they 
had  found  a  god,  and  were  determined  to  worship  it. 

And  so  it  came  to  be  established  as  a  fixed  belief  among 
engineers  and  architects  that  the  best  cement  was  the  one  which 
tested  the  highest,  and  the  manufacturer  had  no  alternative  but  to 
strive  to  make  his  product  test  as  high  as  possible. 

The  next  step  was  in  the  direction  of  forcing  higher  tests  by 
using  an  excess  of  carbonate  of  lime,  or  by  adulterations. 

Henry  Reid  in  his  work  on  "  Portland  Cement,"  London  1877, 
page  315,  says:  "The  presence  of  free  lime  thus  unconverted  is 
now  frequently  due  to  an  over-dose  of  carbonate  of  lime  in  the 
cement  mixture  to  enable  it  to  pass  successfully  the  modern  onerous 
tests." 

From  that  time  until  to-day  the  demand  for  higher  tests  has 
been  continuous  and  more  burdensome,  and  the  manufacturer  has  not 
scrupled  to  employ  any  and  every  means  within  his  power  to  accom- 
plish the  required  results.  He  has  to  do  it  or  retire  from  the  field. 

And  thus,  by  an  unfortunate  misinterpretation  of  the  readings  of 
the  tensile-strain  testing  machine,  in  the  early  days  of  its  existence, 
the  opinions  then  formed  have  passed  current  as  sound  and  unques- 
tioned through  all  the  subsequent  years. 

So  strong  and  deep  seated  is  the  belief  to-day  in  the  reliability 
of  the  testing  machine,  that  a  person  who  cares  to  be  considered  as 
"  up  to  date  "  must  express  no  doubt  as  to  its  infallibility. 

An  ideal  hydraulic  cement,  as  already  stated,  can  be  produced 
by  what  is  known  as  the  Portland  process. 

It  would  consist  in  a  selection  of  the  raw  materials  which  were 
found  to  be  best  adapted  for  the  purpose  (special  care  being  taken, 
at  least,  as  to  the  quality  of  the  clay),  and  these  to  be  thoroughly  and 
finely  commingled  in  correct  proportions,  then  calcined  to  a  mild 
clinker,  sufficiently  vitrified  to  produce  a  medium  weight,  and  then 
ground  exceedingly  fine. 


AMERICAN    CEMENTS.  193 

Such  a  cement  would  test  only  about  half  as  high  as  the  present 
so-called  Portlands,  yet  it  would  be  an  ideal  cement. 

It  could  not  be  excelled,  and  could  be  equaled  only  by  a  rock 
cement  having  its  constituent  parts  present  in  exact  chemical  pro- 
portions. 

It  is  only  through  the  engineer  that  any  improvement  may  be 
expected.  He  alone  is  entitled  to  the  doubtful  distinction  of  bringing 
about  the  change  from  the  slow-setting  pasty  Portlands  of  twenty- 
five  or  thirty  years  ago  to  the  harsh,  high  short-time  testing  Port- 
lands of  to-day. 

It  is  neither  pertinent  nor  sound  to  reason  that  because  the 
Portlands  used  twenty-five  or  more  years  ago  may  be  in  good  condi- 
tion to-day,  the  Portlands  of  the  present  are  worthy  of  the  utmost 
confidence,  for  every  person  at  all  conversant  with  the  facts  knows 
that  those  earlier  Portland  cements  tested  but  about  half  as  high  in 
one,  seven,  thirty,  and  ninety  day  tests  as  do  the  Portlands  now  on 
the  market. 

If  an  artificial  cement  of  a  pasty  consistency  should  test  80  Ibs. 
in  one  day,  and  175  Ibs.  at  seven  days,  300  Ibs.  at  six  months,  600  Ibs. 
at  one  year,  i  ,000  Ibs.  at  two  years,  and  i  ,200  Ibs.  at  five  years,  and 
should  be  found  at  that  age  to  be  tough  and  stone-like  in  its  char- 
acter, can  any  one  for  a  moment  doubt  that  such  a  cement  would 
be  infinitely  superior  to  the  harsh,  high  short-time  testing  cements  of 
to-day? 

Is  it  not  worth  while  to  reflect  that  for  every  one  year  that  harsh 
cements  have  been  in  use,  those  of  a  pasty  character  have  been  in 
use  fifty  years  ? 

Is  it  difficult  to  understand  that  it  is  only  the  pasty  cements 
that  eventually  assume  a  stone-like  character,  while  those  that  are 
harsh  inevitably  become  glassy  ? 

It  is  well  known  to  every  manufacturer  that  the  latter  class  is 
much  more  expensive  to  produce,  but  the  manufacturer  has  no  alter- 
native. He  must  produce  such  grades  of  cement  as  the  engineers 
demand. 

It  is  to  the  engineers,  therefore,  as  has  already  been  stated,  that 
any  improvement  may  be  looked  for,  and  the  only  improvement 
needed,  with  respect  to  artificial  cements,  is  to  get  back  to  the 
sensible  Portlands  of  thirty  years  ago. 


194 


AMERICAN    CEMENTS. 


Let  the  engineer  stipulate  that  cements  shall  not  test  below  or 
above  certain  fixed  limits,  and  there  wi'.l  be  an  end  to  this  doctoring 
and  drugging  of  the  artificial  cements,  which  is  resorted  to  simply 
and  solely  for  the  purpose  of  meeting  arbitrary  and  unreasonable 
requirements. 

The  following  table  of  tests  of  English  Portland  Cements  by 
Reginald  Empson  Middleton,  M.  Inst.  C.  E.,  was  printed  in  Engi- 
neer, London,  Vol.  65,  p.  279,  April  6,  1888. 

The  figures  given  represent  the  average  strength  in  pounds  per 
square  inch,  in  tensile  strain,  and  the  ages  in  days  of  the  briquettes 
when  broken. 


No. 

Days. 

Pounds. 

Days. 

Pounds. 

Days. 

Pounds. 

Per  cent,  of 
Loss  or  Gain. 

i 

7 

258 

942 

440 

1325 

Sfo 

Gain. 

"3- 

2 

7 

320 

000 

635 

1283 

577 

Gain. 

75« 

_3  

4 

7 

37' 

982 

560 

1365 

5W 

Gain. 

61. 

7 

419 

1040 

435 

1423 

492 

Gain. 

18. 

5 
6 

7 
7 

479 

1088 

542 

M7i 

_55J  
526 

Gain  . 

»5 

534 

858 

545 

1241 

Loss. 

'•5 

This  table  discloses  the  fact  that  artificial  cements  which  at 
seven  days  test  from  250  to  350  Ibs.  show  higher  ultimate  results 
than  those  which  at  seven  days  test  400  to  600  Ibs. 

The  following  quotation  from  the  "  Transactions  of  the  German 
Association  of  Cement  Makers  "  discloses  either  a  deplorable  lack  of 
common  honesty  or  a  desperate  attempt  at  fulfilling  the  severe  re- 
quirements of  engineers.  "In  order  to  obtain  the  best  results  (?) 
the  amount  of  plaster  of  Paris  used  must  be  proportionately  in- 
creased in  accordance  with  the  quantity  of  ground  slag  employed." 
Presuming  it  to  be  a  case  of  necessity  rather  than  a  lack  of  common 
honesty,  what  a  commentary  on  the  straits  to  which  the  producers  are 
reduced  to  meet  the  requirements  of  engineers,  knowing,  as  all  manu- 
facturers do  know,  that  plaster  of  Paris  is  in  no  sense  hydraulic, 
although  it  tests  neat  as  high  as  250  Ibs.  per  square  inch  in  tensile 
strain  in  twenty-four  hours. 

The  time  must  surely  come  when  it  will  be  well  understood  that 
any  and  all  schemes  of  hot-house  forcing,  for  the  purpose  of  obtain- 
ing high  seven-day  tests,  constitute  an  unnatural  interference  with 


AMERICAN   CEMENTS.  195 

the  crystallization  of  true  silicates,  and  are  therefore  a  serious  dam- 
age to  their  most  desirable  qualities  of  endurance. 

Verily  it  is  the  pace  that  kills,  and  even  when  applied  to  hy- 
draulic cements,  there  is,  if  we  may  be  permitted  to  employ  it,  no 
truer  saying  than  "  Soon  ripe,  soon  rotten." 

For  hydraulic  purposes  there  is  no  known  substance  that  can  in 
any  way  aid  or  improve  the  quality  of  pure  unadulterated  hydraulic 
silicates,  when  left  to  crystallize  in  their  own  natural  way. 

THE   BOILING   TEST. 

During  the  past  few  years  it  has  become  quite  the  fashion  to 
boil  samples  of  cement  in  order  to  test  their  qualities. 

If  one  brand  sustains  the  test  without  serious  results  it  is  con- 
sidered superior  to  others  which  fall  down  during  the  boiling.  This 
is  about  as  wise  and  logical  a  conclusion  as  that  arrived  at  by  some 
of  our  good  old  Puritan  fathers  during  the  witchcraft  craze. 

The  witch,  being  thrown  into  a  pond,  if  she  went  to  the  bottom 
and  stayed  there,  was  considered  innocent.  But  if  she  managed  to 
float,  she  was  deemed  to  be  possessed  of  the  devil,  and  was  then 
forced  to  the  bottom  on  general  principles. 

By  the  boiling  test,  many  of  our  very  best  brands  of  cement  are 
condemned. 

It  is  safe  to  assert  that  of  the  more  than  one  hundred  and  fifty 
million  barrels  of  American  Rock  cements  used  in  all  the  great  en- 
gineering works  throughout  the  country  during  the  past  fifty  years, 
and  with  no  evidences  of  failure,  not  i  per  cent,  would  have  sus- 
tained the  boiling  test. 

A  cement,  whether  natural  or  artificial,  that  will  crystallize  so 
rapidly  as  to  sustain  the  boiling  test,  ought  to  be  looked  upon  with 
suspicion,  as  it  is  either  naturally  too  quick  setting,  or  is  too  fresh 
and  lacking  in  proper  seasoning. 

FREEZING   TEST. 

The  many  experiments  that  have  been  made  by  different 
authorities  in  the  freezing  of  green  cement  samples  would  seem  to 
indicate  that  Portland  cement  mortar  will  sustain  severe  freezing 
without  appreciable  disturbance  of  the  exposed  surfaces,  but  it 
suffers  in  loss  of  strength  in  some  cases  as  much  as  50  per  cent. 


196 


AMERICAN    CEMENTS. 


While  the  Rock  cement  mortars  will  show  disintegration  to  the 
extent  of  X  to  Yz  m-  on  the  exposed  surfaces,  yet  the  portions  not 
disintegrated  are  shown  to  have  sustained  no  loss  in  strength,  and 
in  some  instances  the  strength  is  above  the  normal. 

A  series  of  tests  made  by  the  author,  the  results  of  which  are 
herewith  tabulated,  differ  somewhat  from  those  of  other  writers,  re- 
sulting, no  doubt,  from  having  experimented  with  different  brands 
of  cement. 

All  of  the  briquettes  were  given  one  day  in  air  and  six  days  in 
water,  those  in  the  second  column  being  placed  in  water  and  set 
outside,  where  they  were  soon  frozen,  and  so  remained  in  solid  ice, 
until  thawed  out  and  broken  at  the  end  of  the  seventh  day. 

All  of  the  briquettes  represented  in  the  second  column,   after 

TABLE    OF    TESTS     OF    THE    RELATIVE    STRENGTH    OF   FROZEN    AND 
UNFROZEN    SAMPLES    OF    THE   SAME    CEMENT. 


No.  of  Column. 

i 

2 

3 

4 

5 

Kinds  of 
Cement. 

Not 
Frozen. 

Frozen. 

Per  cent,   of 
loss  by 
freezing. 

Per  square 
inch  of 
the  frozen 
samples. 

Per  cent,  of  loss  or 
gain   by  freezing, 
of  equal  areas. 

Medium  Burned 
Rock  Cement. 

138 

J35 

2.17 

194 

Gain. 

40 

Hard  Burned 
Rock  Cement. 

226 

225 

0.44 

323 

Gain. 

43 

Slow  Setting 
Portland. 

388 

280 

27.83 

402 

Gain. 

04 

Medium 
Setting  Portland. 

419 

2Q2 

30-31 

419 

Gain. 

00 

Quick  Setting 
Portland. 

433 

2*5 

41.11 

366 

Loss. 

'5 

being  thawed  out,  were  shown  to  have  lost  equally  in  area,  by  scale 
and  disintegration  to  the  depth  of  y£  in.  on  all  sides. 

There  was  no  appreciable  difference  in  the  losses,  the  Portlands 
having  suffered  equally,  in  that  respect,  with  the  Rock  cements. 

The  figures  in  the  second  column  show  the  actual  breaking 
strain  of  the  frozen  briquettes,  but  it  will  be  borne  in  mind  that  the 
areas  of  these  briquettes  were  greatly  lessened  by  freezing ;  there- 
fore the  percentage  of  loss  in  strength,  as  shown  in  the  third  column, 
represents  the  loss  without  regard  to  actual  areas. 

The  fourth  column  represents  the  strength  of  the  samples  in 


AMERICAN    CEMENTS.  197 

the  second  column  when  calculated  at  I  full  square  inch,  or  equal  in 
area  to  the  samples  in  the  first  column. 

The  fifth  column  represents  gain  or  loss  in  strength  of  the  frozen 
samples,  with  equal  areas  of  the  unfrozen  ones. 

All  of  the  briquettes  were  gaged  neat  by  the  same  person,  and 
were  treated  alike  as  to  plasticity  and  temperature. 

There  is  a  surprising  gain  in  strength  of  the  Rock  cements  by 
freezing.  With  the  Portlands,  the  slow  and  medium  setting  samples 
held  their  own,  while  the  higher  testing  Portland,  under  ordinary  rules 
lost  1 5  per  cent,  in  strength  of  equal  areas  by  freezing. 

It  is  not  good  practise  to  use  any  kind  of  cement  in  cold 
weather,  especially  when  it  freezes  during  the  night  and  thaws  during 
the  day,  and  should  be  avoided  whenever  possible. 

COLOR. 

There  is  no  one  feature  connected  with  the  subject  of  cements 
which  exerts  a  stronger  influence  in  the  building  up  of  opinions  con- 
cerning the  qualities  of  a  cement  than  that  of  color. 

The  belief  is  almost  universal  that  a  good  dark  color  is  a  sure 
indication  of  a  good  strong  cement. 

The  tester  is  an  exception  who  does  not  express  surprise  when  he 
finds  a  light-colored  cement  testing  higher  than  a  dark  one ;  and  he  al- 
most invariably  attributes  the  cause  to  some  defect  in  his  dark  bri  quettes. 

If  he  should  be  told  that  the  way  it  came  to  be  discovered  that 
the  world  was  round,  and  revolved  on  its  axis,  was  by  observing  that 
people  who  did  much  walking  in  easterly  and  westerly  directions 
invariably  ran  the  heels  of  their  shoes  down  at  the  back,  while  those 
who  wore  theirs  off  at  the  sides  were  found  to  do  most  of  their  walk- 
ing in  northerly  and  southerly  directions,  he  would  feel  that  his  in- 
telligence had  been  called  in  question ;  but  it  would  not  occur  to  him 
that  his  own  theory  in  regard  to  the  color  of  a  cement  was  equally  as 
whimsical.  It  is  remarkable  how  strong  a  hold  some  absurd  preju- 
dices have  upon  the  general  public.  It  was  not  so  very  many  years  ago 
that  any  brand  of  Western  flour,  to  obtain  a  market  in  the  Eastern 
States,  had  to  be  put  up  in  round-hooped  barrels. 

For  more  than  a  third  of  a  century  it  has  been  repeatedly 
stated  that  the  color  in  a  cement  was  due  to  the  presence  of  a  small 


198  .          AMERICAN    CEMENTS. 

amount  of  oxide  of  iron,  and  that  in  no  manner  did  its  presence 
affect  the  quality  of  a  cement. 

General  Gillmore  so  stated  it  in  his  treatise  on  "  Limes,  Cements, 
and  Mortars,"  issued  thirty-five  years  ago  ;  and  the  same  statement 
has  been  made  by  various  writers  during  all  the  subsequent  years. 
Yet  the  belief  prevails  that  color  has  to  do  with  the  quality. 

So  strong  is  this  prejudice,  that  manufacturers  of  Portland  ce- 
ments, when  they  find  that  their  available  clay  does  not  carry  sufficient 
oxide  of  iron  to  give  the  requisite  color  to  their  product,  resort  to  the 
use  of  artificial  coloring  matter,  on  account  of  the  difficulty  experi- 
enced in  finding  a  market  for  light-colored  Portland. 

Any  coloring  matter,  whether  in  a  natural  or  an  artificial  cement, 
is  an  adulteration,  and  is  inherent  in  the  Rock  cements,  while  it  may 
or  may  not  be  so  in  the  artificial  product. 

In  the  Rock  cements  the  oxide  of  iron  is  closely  associated  with 
the  clay,  and  its  quantity,  as  a  rule,  governs  the  shade  of  coloring 
given  to  the  cement. 

If  the  amount  is  small  and  the  calcination  is  light,  the  color  of 
the  cement  will  be  a  pale  yellow.  But  with  a  higher  degree  of  cal- 
cination, the  color  becomes  a  deeper  yellow,  or  a  light  or  a  dark  drab, 
dependent  upon  the  intensity  and  duration  of  the  heat. 

If  the  amount  is  large,  the  cement  will  be  light  to  dark  brown, 
according  to  the  intensity  and  duration  of  the  heat. 

Whatever  may  be  the  color  of  a  cement,  its  quality  is  in  no  way 
affected  thereby,  unless  the  amount  of  coloring  matter  is  excessive. 

The  quality  of  a  cement  is  governed  by  three  important  require- 
ments, no  one  of  which  can  safely  be  dispensed  with,  namely  :  — • 

First,  a  proper  proportion  of  the  essential  ingredients,  /.  ^., 
silica,  lime,  magnesia,  and  alumina. 

Second,  a  proper  calcination,  which  must  be  varied  to  suit  the 
requirements  of  varying  proportions  of  the  constituent  parts. 

Third,  fine  grinding. 

It  will  be  seen,  then,  that  a  cement  may  be  either  light  or  dark, 
and  yet  be  of  good  quality,  while  a  very  poor  quality  of  cement 
may  be  accompanied  by  the  most  taking  shade  of  colors. 

And  yet,  inasmuch  as  the  constituent  parts  named,  when  free 
from  impurities,  are  white,  it  cannot  but  be  clear  that  an  absolutely 
pure  cement  cannot  be  otherwise  than  white. 


AMERICAN    CEMENTS.  199 

The  Rock  cements  are  never  colored  artificially,  and  so  we  find 
as  many  variations  in  color  as  there  are  different  manufacturing 
centers,  each  having  its  own  peculiar  shade  or  tint,  while  the  differ- 
ent brands  of  the  same  locality  are  usually  of  the  same  color,  yet 
they  may  vary  considerably  in  quality. 

With  the  artificial  cements,  the  natural  coloring  matter  is  to  be 
found  in  the  clay,  the  same  as  with  the  Rock  cements,  and,  as  has 
been  stated,  when  this  is  insufficient  to  suit  the  prevailing  taste  (?) 
resort  is  had  to  artificial  coloring  by  the  use  of  some  form  of  carbon, 
or  pigments. 

Though  the  appearance  of  Portland  cement,  unadulterated  with 
extraneous  coloring  matter,  is  an  indication  of  its  merits,  it  is  clear 
that  if  artificial  coloring  matter  is  employed,  the  appearance  of  the 
cement  is  no  criterion  of  its  quality. 

TENSILE   TESTS. 

The  system  of  arriving  at  the  value  of  a  cement  by  means  of 
the  tensile-strain  testing  machine  has  grown  to  such  proportions,  and 
is  so  universally  relied  upon,  believed  in,  and  so  seriously  regarded 
as  the  Ultima  Thule  of  all  the  knowledge  necessary  to  determine 
values,  and  make  or  unmake  a  cement  in  the  public  opinion,  that  it 
seems  almost  sacrilegious  to  disturb  the  serenity  of  the  faithful 
followers  of  this  modern  Juggernaut,  who,  metaphorically,  throw  them- 
selves under  its  sacred  wheels. 

And  yet  the  system  is  so  permeated  with  inaccuracies,  incon- 
sistencies, and  absurdities,  that  the  temptation  to  puncture  the  vener- 
able humbug  is  well-nigh  irresistible. 

The  system  contains  many  features  in  common  with  the  alleged 
virtues  of  the  divining  rod. 

And,  although  the  comparison  may  seem  odious  to  a  large 
majority  of  the  champions  of  the  tensile  test  system,  yet  the  author 
feels  measurably  assured  that  a  few,  at  least,  of  the  undoubted  facts 
which  he  may  present  will  be  recognized  at  sight  by  many  engineers 
and  architects  whose  experiences  with  the  system  have  led  them  into 
labyrinths  of  uncertainty  and  doubt. 

The  following  from  a  paper  on  "  The  Divining  Rod,"  presented  by 
R.  W.  Raymond  at  the  Boston  meeting  of  the  American  Institute  of 
Mining  Engineers,  in  February,  1883,  is  sufficient  to  illustrate  the 
parallel :  — • 


200  AMERICAN    CEMENTS. 

"First.  The  immense  literature  of  the  divining  rod  shows 
nothing  more  clearly  than  the  boundless  confusions  and  contradictions 
of  its  advocates  and  professors. 

"  Second.  Of  the  dozen  different  schools  of  practise,  each  is 
necessarily  obliged  to  reject  half  of  the  asserted  principles  and  certi- 
fied facts  put  forward  by  the  rest. 

"  Third.  It  will  be  remembered  that  the  Egyptian  sorcerers 
confronted  by  Moses  carried  rods,  as  Moses  and  Aaron  also  did. 

"  Fourth.  Cicero,  who  had  himself  been  an  augur,  says,  in  his 
treatise  on  divination,  that  he  does  not  see  how  two  augurs,  meeting 
in  the  street,  could  look  each  other  in  the  face  without  laughing. 

"  Fifth.  The  following  formula,  cited  by  Gaetzschmann,  may 
serve  as  an  example  :  — 

" «  In  the  name  of  the  Father,  and  the  Son,  and  of  the  Holy 
Ghost,  I  adjure  thee,  Augusta  Carolina,  that  thou  tell  me  how 
many  fathoms  is  it  from  here  to  the  ore.' " 

One  has  but  to  consider  that  if  a  package  of  any  brand  of  cement 
is  divided  among  fifty  expert  testers,  to  be  made  up  into  briquettes, 
all  the  testers  being  governed  by  one  set  of  rules,  as  to  time,  tempera- 
tures, percentage  of  water  to  be  used,  and  the  other  ordinary  require- 
ments, the  breakings,  when  tabulated,  will  show  fifty  tables  of  tests, 
no  two  of  which  will  be  alike.  In  fact,  they  will  vary  from  each 
other  all  the  way  from  i  to  300  per  cent.,  and  so,  if  in  the  first  para- 
graph of  the  quotation  we  insert  "  tensile  tests "  in  the  place  of 
"divining  rod,"  we  come  near  to  describing  the  present  chaotic  state 
of  the  art  of  briquette  making,  and,  in  the  fourth  paragraph,  in  the 
place  of  "  two  augurs  "  read  "  two  testers,"  after  they  have  stood  side 
by  side  at  the  same  table,  and  have  each  made  and  tested  five  bri- 
quettes from  the  same  sample  of  cement,  and  find  the  results  from 
50  to  200  Ibs.  apart. 

And  as  to  the  fifth  paragraph,  let  us  read  it  thus,  "  In  the  name 
of  the  American  Society  of  Civil  Engineers,  and  all  the  other  socie- 
ties under  the  sun,  whose  members  practise  the  art  of  cement  testing 
by  tensile  strain,  I  adjure  thee,  O  thou  testing  machine,  to  tell  me 
whether  it  is  thy  fault  that  I  am  thus  befuddled,  or  am  I  drifting 
into  incipient  idiocy." 

A  tester  makes  up  briquettes  and  tests  them  from  a  given  brand 
of  cement,  and  reports  to  his  superior  that  "  the  cement  runs  very 


AMERICAN    CEMENTS.  201 

uneven."  The  fact  that  it  is  his  briquettes  and  not  the  cement  which 
"  runs  very  uneven  "  never  occurs  to  this  knight  of  the  testing 
machine. 

When  Don  Quixote  made  his  famous^  charge  on  the  windmills 
and  was  unceremoniously  overthrown,  he  had  the  courage  to  beat  a 
rather  undignified  retreat. 

But  not  so  with  our  knight  of  the  testing  machine.  He  may  be 
overthrown  day  after  day,  but  he  does  not  know  it,  and  with  an  as- 
surance bordering  on  the  sublime  he  will  tell  you  that  such  and  such 
a  brand  of  cement  is  not  first  class,  for  he  has  tested  it,  and  the 
cement  is  not  up  to  the  requirements,  for  it  "runs  very  uneven." 

It  is  useless  to  confront  him  with  the  fact  that  other  expert 
testers  have  found  that  the  brand  in  question  tests  above  the  require- 
ments, for,  lacking  the  prudence  of  Don  Quixote,  he  is  overthrown, 
but  does  not  realize  it,  when  he  says  he  "  can  get  now  and  then  a 
briquette  to  come  up  to  or  even  go  beyond  the  requirements,  but  it 
will  not  average  (?)  more  than  as  shown  in  his  tables." 

It  is  probable  that  we  are  indebted  to  the  engineers  of  a  past 
generation  for  that  altogether  brilliant  idea  of  giving  a  brand  of 
cement  a  record  based  on  its  average  (?)  breakings.  And  for  some 
unaccountable  reason  its  utter  absurdity  seems  to  have  escaped  the 
notice  of  the  ablest  engineers  of  to-day. 

If  a  trotting  horse  should  be  sent  to  the  track,  on  a  trial  of  three 
one-mile  heats,  for  the  express  purpose  of  making  a  record,  and  the 
three  trials  should  result  as  follows :  — 

min.  sec. 
ist    heat,  2.15 
2d       „       2.20 
3d       „      2.10 

total  time     6.45 

would  we  calculate  the  time  thus,  6.45  -=-  3  =  average  time  2.15, 
and  seriously  contend  that  the  horse  takes  a  record  of  2.15  ? 

Should  this  be  done,  the  whole  trotting  world  would  smile,  and 
yet  it  would  be  no  more  absurd  than  it  is  to  give  a  cement  a  record 
based  on  the  average  (?)  result  of  breaking  strains  of  three  or  five 
briquettes,  made  from  the  same  sample  of  cement. 


202 


AMERICAN   CEMENTS. 


The  tester  makes  three  briquettes  from  a  single  small  sample  of 
cement,  and  no  one  will  deny  that  it  is  precisely  the  same  in  all  its 
parts,  and  to  the  best  of  the  tester's  knowledge  and  belief,  he  has 
made  the  briquettes  precisely  alike.  He  has  treated  them  alike  as 
to  every  known  detail,  and  yet  one  breaks  at  100  Ibs.,  while  the 
others  fall  off  30  and  60  Ibs.  respectively,  and  the  engineer,  while 
knowing  these  results,  from  habit  or  custom,  permits  the  cement  to 
be  deprived  of  its  just  record,  which  in  this  instance  is  none  other 
than  100  Ibs.,  and  the  record  is  fixed  at  70  Ibs. 

If  one  portion  of  the  sample  tested  100  Ibs.,  surely  it  is  not  the 
fault  of  the  cement  that  the  balance  did  not,  and  the  conclusion  is 
inevitable  that  it  is  the  tester  who  is  at  fault.  But  the  fault  is  laid 
to  the  cement,  and  so  this  inanimate  though  wonder-working  mate- 
rial suffers  in  reputation  by  the  carelessness  and  blunders  of  the 
average  knight  of  the  testing  machine. 

During  the  construction  of  the  new  Croton  Aqueduct  at  New 
York,  a  certain  brand  of  Rock  cement  was  tested  in  one-day  neat 
tests  by  two  sets  of  testers,  — 

835  briquettes  made  by  one  set  of  three  testers  averaged  62  T35   Ibs. 
2434         „•  »  »  »         ten          „  „         85  &     „ 

a  difference  of  nearly  35  per  cent.,  and  yet  one  set  of  rules  governed 
all  the  testers,  and  the  tests  were  made  daily  from  the  same  consign- 
ments of  cement. 

From  the  table  of  tests  of  Mr.  Thompson,  City  Engineer,  Peoria, 
111.,  as  shown  in  connection  with  his  specifications  as  herein  given, 
the  following  are  selected  from  a  large  number,  as  a  fair  example  of 
one-day  neat  tests  of  Rock  cement. 


No. 

No.  of 
Samples. 

Highest. 

Lowest. 

Average. 

Per  Cent. 
Variation. 

r 

8 

118 

45 

77 

162 

2 

6 

'38 

80 

109 

V% 

3 

6 

104 

fs 

79 

60 

4 

10 

103 

47 

65 

119 

1 

I 

142 
M3 

So 
48 

79 
70 

184 

198 

7 

9 

MI                            57 

122 

'45 

8 

8 

167 

80 

140 

108 

Mr.  Thompson's  tables  contain  the  unusual  merit  of  showing 
the  highest  and  lowest  breakings. 


AMERICAN    CEMENTS.  203 

The  absurdity  of  giving  a  cement  a  record  on  the  average  (?) 
system  is  well  demonstrated  in  No.  6  of  the  table. 

The  eight  samples  were  made  from  the  same  cement.  One  of 
the  briquettes  happened  to  be  well  made,  and  it  tested  143  Ibs., 
and  yet  it  takes  a  record  of  barely  one  half  that  figure.  It  is  deprived 
of  its  just  and  true  record  presumably  because  the  briquette  maker, 
when  he  made  the  one  which  tested  only  48  Ibs.,  was  either  very 
tired,  or  careless,  or  was  unduly  hurried. 

The  table  given  is  not  an  exceptional  one.  Tables  as  uneven 
as  this  are  to  be  found  in  nearly  every  cement-testing  establishment 
in  the  country,  and  it  has  always  been  so  since  the  tensile  test  mania 
began,  over  a  third  of  a  century  ago. 

The  prevailing  practise  in  the  making  of  briquettes  is  to  apply 
sufficient  water  to  produce  the  proper  degree  of  plasticity,  thereby 
enabling  the  operator  to  press  the  material  into  the  molds  with  the 
thumbs  or  a  trowel. 

This  method  is  supposed  to  attain  medium  results,  and  is  advo- 
cated by  engineers  generally,  under  the  impression  that  the  breakings 
of  such  briquettes  indicate  quite  closely  the  actual  strength  of  the 
cement  in  the  masonry  in  which  it  is  used. 

However  true  this  theory  may  be,  it  opens  the  door  to  a  wide 
diversity  of  results,  as  each  briquette  maker  is  a  law  unto  himself  as 
to  what  constitutes  the  proper  degree  of  plasticity  of  the  material ; 
and  herein  lies  the  chief  cause  of  the  surprising  difference  in  the 
strength  of  briquettes  made  up  from  a  single  sample  of  cement. 

The  author  has  for  many  years  been  firm  in  the  belief  that  the 
only  correct  way  to  test  a  cement  by  tensile  strain  is  to  use  just 
enough  water  to  properly  hydrate  the  silicates,  then  pack  the  mate- 
rial into  the  molds,  making  the  briquettes  as  dense  and  solid  as 
is  possible,  by  tamping  or  ramming,  the  object  being  at  all  times  to 
make  the  briquettes  test  to  the  utmost  limit  of  the  strength  of  the 
cement.  We  would  then  know  the  capabilities  of  each  brand  tested. 

There  is  a  satisfaction  in  knowing  the  full  strength  of  a  cement 
whether  or  not  it  is  ever  called  into  practise  in  masonry. 

Once  the  full  strength  of  a  cement  is  known,  it  becomes  an 
easy  matter  to  estimate  the  strength  values  of  different  degrees  of 
plasticity. 

By  this  method  we  avoid  the  contradictory  and  unsatisfactory 


204  AMERICAN    CEMENTS. 

variations  which  continually  arise  among  different  testers  of  the 
same  brand,  which  will  always  obtain  so  long  as  moderate  results 
only  are  aimed  at. 

So  long  as  the  qualities  of  our  cements  are  to  be  measured  by 
tensile  strain  tests,  there  is  no  good  reason  why  the  system  should 
not  be  open  to  improvement. 

If  it  is  self-evident  that  to  the  system  of  aiming  at  moderate  or 
medium  results  is  due  the  variations  which  are  often  so  wide  as  to 
be  really  grotesque,  why  not  abolish  such  a  system  and  adopt  that 
which  will  give  us  without  question  a  full  knowledge  of  the  highest 
limit  of  strength  in  the  cement,  and  at  the  same  time  reveal  to  us  all 
its  capabilities  ?  And,  instead  of  giving  a  cement  a  record  based  on 
the  average  breakings  of  five  briquettes,  a  most  absurd  and  indefen- 
sible system,  let  the  highest  testing  briquette  of  the  five  make  the 
record  of  the  cement. 

It  is  only  by  the  employment  of  this  system  that  the  question  of 
the  relative  strength  of  different  brands  of  cement  can  ever  be 
settled. 

It  is  the  only  system  that  is  fair  to  all  brands  of  cement.  This 
is  shown  by  the  wonderful  uniformity  of  breakings  of  briquettes 
made  from  any  brand  of  cement  where  the  aim  has  been  to  get  the 
highest  possible  results. 

In  nearly  all  the  tables  of  tests  that  are  published  where  the 
records  of  several  brands  of  cement  have  been  carried  along  for  any 
length  of  time,  it  will  be  observed  that  one  or  more  of  the  brands 
will  fall  off  in  a  most  inexplicable  manner. 

Perhaps  the  records  are  higher  at  three  months  than  they  are  at 
six,  or  even  nine  months,  and  yet  at  twelve  months  they  may  have 
recovered  all  the  lost  ground,  or  even  have  made  a  substantial  gain ; 
and  so  we  often  notice  in  long-time  tests  that  a  cement  may  show  a 
strength  of,  say,  500  Ibs.  at  one  year,  and  400  Ibs.  at  two  years,  while 
the  three  years'  column  will  show  600  Ibs. 

This  uncomfortable  feature  is  common  to  the  Rock  and  Port- 
land cements  alike. 

Should  such  an  uneven  showing  of  one  brand  be  recorded  in  a 
table  among  other  brands  which  show  a  steady  gain,  the  comparison 
is  naturally  unfavorable  to  the  one  with  the  unsteady  record. 


AMERICAN    CEMENTS.  205 

In  fact,  it  is  not  at  all  unusual  to  meet  with  those  in  authority 
who  will  unequivocally  express  a  preference  for  the  cement  showing 
the  more  steady  record,  even  though  the  brand  which  has  fallen  off 
may  have  surpassed  all  the  others  at  the  final  closing  of  the  table. 

The  explanation  for  this  curious  phase  of  the  subject  is  found 
in  the  deep-seated  and  profound  faith  in  the  infallibility  of  the  testing 
machine. 

If  three  briquettes  are  made  from  a  single  sample  of  cement  by 
one  person  and  they  are  treated  alike  until  broken  at  six,  nine,  and 
twelve  months,  and  the  breakings  are  500,  400,  and  600  Ibs.  respec- 
tively, nothing  is  more  certain  than  that  the  briquette  which  was 
broken  at  nine  months  was  not  as  well  made  as  the  others. 

If  a  cement  is  really  weaker  at  nine  months  than  it  is  at  six 
months,  it  is  simply  impossible  for  it  to  show  any  gain  in  the  twelve 
months'  test. 

The  absurdity  of  a  cement  gaining  and  losing  in  strength  alter- 
nately must  be  apparent  to  any  person  who  will  study  the  cause  of 
its  setting  and  hardening. 

In  the  testing  of  cements  by  tensile  strain  the  engineer  meets 
with  many  conditions  which  seem  to  puzzle  and  confuse,  among 
which  may  be  noted  that  it  oftentimes  happens  in  the  testing  of  two 
or  more  brands  of  cement  neat,  and  in  sand  mixtures,  that  although 
the  brands  may  be  equal  in  fineness,  the  same  quality  of  sand  used 
for  all,  and  all  the  briquettes  made  by  the  same  person,  yet  the  ce- 
ment which  tests  the  highest  neat  tests  the  lowest  in  the  sand  mixtures. 

Rarely  more  than  one  set  of  tests  is  made,  and  so  the  tables  are 
made  up,  and  it  is  recorded  against  the  highest  testing  cement  that 
it  "  tests  high  in  neat  tests,  but  cannot  carry  sand  equal  to  the  lower 
testing  brands." 

This  is  a  condition  which  often  confronts  the  engineer,  and, 
strangely  enough,  the  opinion  formed  is  almost  invariably  adverse  to 
the  brand  testing  the  lowest  with  sand  mixtures,  although  showing 
the  highest  in  the  neat  tests. 

In  ninety-nine  cases  in  every  one  hundred  the  opinion  would  be 
corrected  by  further  tests,  for  it  is  certain  that  all  conditions  being 
equal,  the  cement  testing  the  highest  in  neat  tests  will  also  test 
highest  in  sand  mixtures,  and  the  failure  to  do  so  may  be  looked  for 
in  the  imperfect  manner  of  making  the  briquettes. 


206  AMERICAN    CEMENTS. 

The  only  possible  exception  to  the  rule  will  be  found  in  the  fact 
that  a  cement  containing  an  excess  of  clay  may  test  high  in  neat 
tests,  yet  will  not  carry  sand  equal  to  one  that  is  correctly  pro- 
portioned. 

But  such  cements  are  so  exceedingly  rare  in  this  country  that 
the  rule  may  be  said  to  hold  good,  that  the  fault  is  in  the  making  of 
the  briquettes. 

There  are  thousands  of  masons  and  contractors  throughout  the 
country  who  buy  and  use  cements,  in  the  construction  of  cisterns, 
cellar  floors,  sidewalks,  milldams,  foundation  walls,  and  for  various 
other  purposes,  who  have  no  mechanical  means  for  testing  the 
cements  they  are  using. 

To  such  we  suggest  the  following  method. 

Although  the  process  is  very  simple  and  easy  to  practise,  yet  it 
involves  a  principle  which  embraces  the  chief  and  most  valuable 
features  of  all  other  tests. 

In  fact,  it  may  be  said  that  there  are  no  known  methods  for 
testing  the  hydraulicity  of  a  cement  which  for  effectiveness  and 
reliability  can  compare  with  it. 

The  author  has  employed  this  method,  whenever  occasion  has 
arisen,  during  the  past  thirty  years,  and  he  has  never  known  it  to  fail 
to  detect  and  expose  weaknesses  or  imperfections,  if  they  exist  in  the 
cement. 

In  the  practise  of  this  method  it  is  only  necessary  to  make  a 
mold  with  which  to  form  bars  of  cement. 

All  that  is  necessary  for  this  purpose  is  a  piece  of  hardwood 
plank  3  ins.  wide,  2  ins.  thick,  and  12  ins.  long. 

Mortise  into  one  side  of  this  bit  of  wood  a  cavity  i  l/z  ins.  wide, 
I  in.  deep,  and  8  ins.  long,  making  the  sides  and  ends  slightly  beveled, 
which,  with  the  bottom,  should  be  made  smooth,  and  then  the  cavity 
should  be  well  oiled,  after  which  it  is  ready  for  use. 

Wet  up  a  sample  of  the  cement  to  be  tested  into  a  stiff  paste, 
and  with  a  trowel  press  it  in  firmly,  and  smooth  it  off  level  with  the 
face  of  the  mold. 

After  the  cement  has  hardened,  which  will  occur  in  from  twenty 
minutes  to  two  hours,  turn  the  mold  bottom  up,  and  let  it  rest  on 
supports  yz  in.  thick  under  each  end. 

By  careful  jarring  the  cement  bar  will  drop  out  of  the  mold. 


AMERICAN    CEMENTS.  207 

Place  the  bar  on  the  broad  side  in  a  pan  or  box,  with  the  ends 
resting  on  supports  in  such  manner  that  at  least  6  ins.  of  the  length 
of  the  bar  shall  be  free  and  clear  underneath,  with  a  vertical  clear- 
ance of  i  to  2  ins. 

Next,  fill  the  receptacle  with  water  until  the  cement  bar  is  com- 
pletely submerged. 

If  the  cement  is  strong  in  hydraulicity,  the  bar  will  maintain  its 
shape  indefinitely ;  but  if  it  is  lacking  in  this  quality,  or  is  weak,  or 
defective  in  its  composition  or  manufacture,  it  is  sure  to  give  way 
between  the  supports. 

The  author  has  known  of  rare  cases  where  the  bar  maintained 
its  shape  ten  days  and  then  collapsed,  but  the  ordinary  defects  in  a 
cement  will  be  made  manifest  within  twenty-four  hours. 

Bars  made  with  sand  mixtures,  of  course,  require  a  longer  time 
to  harden  than  those  made  from  neat  cements,  and,  therefore,  should 
be  given  a  full  opportunity  to  crystallize  before  submersion. 

In  closing  our  chapter  on  the  testing  of  cements,  the  thought 
arises,  which,  although  somewhat  tinged  with  impertinence,  will  not 
be  dismissed  without  expression. 

In  our  first  chapter  we  quoted  from  "  Hydraulic  Mortars,"  by 
Dr.  Michaelis,  Leipzig,  1869,  as  follows:  "The  Eddystone  Light- 
house is  the  foundation  upon  which  our  knowledge  of  hydraulic 
mortars  has  been  erected,  and  it  is  the  chief  pillar  of  our  architec- 
ture." 

This  sentence  covers  a  great  deal  of  ground,  and  is  worthy  of 
much  thought  and  consideration ;  and  granting  that  it  is  true,  we  are 
lost  in  conjecture  as  to  what  John  Smeaton  would  have  done  when 
he  built  the  Eddystone  Lighthouse,  had  the  cement  which  he  used  in 
the  construction  of  that  famous  tower  been  passed  upon  by  a 
British  government  engineer,  with  a  tensile  strain  testing  machine  as 
his  guide,  and  governed  by  the  absurd  rules  and  specifications,  for 
this  cement  could  not  possibly  have  tested  25  Ibs.  per  square  inch  in 
a  seven-day  neat  test. 

What  would  be  thought  of  the  manufacturer  of  to-day  who 
would  have  the  temerity  to  offer  such  a  quality  of  cement  for  the 
construction  of  a  lighthouse  in  this  country  or  in  Europe? 

Everybody  knows  he  would  be  ridiculed,  for  it  is  a  question  if 
Rock  cement  testing  150  Ibs.  in  seven  days  would  be  considered 


208  AMERICAN    CEMENTS. 

strong  enough,  and  it  is  more  than  likely  that  a  Portland  testing 
400  Ibs.  in  a  seven-day  neat  test  would  be  required. 

Yet  the  Eddystone  Lighthouse  stood  in  good  condition  over 
one  hundred  and  twenty  years,  until  taken  down  to  make  way  for  a 
larger  structure  ;  and  the  mortar  was  found  all  that  could  be  desired. 

This  being  true,  what  becomes  of  our  boasted  advance  in  the 
art  of  cement  making? 

Where  can  we  find  a  more  trying  place  for  a  cement  mortar 
than  in  the  stone  walls  of  a  lighthouse  standing  out  in  the  open  sea  ? 

Wherein  lies  the  benefit  of  using  a  high-testing  cement  for  such 
work,  when  a  cement  of  the  quality  of  the  Aberthaw  hydraulic  lime 
used  by  Smeaton  in  the  walls  of  the  Eddystone  Lighthouse  can  be 
supplied  in  this  country  for  less  than  one  fourth  the  cost  of  the  high- 
testing  cement  ? 

If  we  care  to  build  for  all  time,  we  must  remember  that  that 
which  causes  a  cement  to  set  promptly  in  water  also  causes  its  com- 
paratively early  disintegration  when  exposed  to  the  atmosphere. 

A  cement,  therefore,  which  requires  sixty  or  ninety  days  to 
harden  in  exposed  masonry  will  be  found  in  perfect  condition  ages 
after  the  mortar  made  from  quick-setting  cements  has  crumbled  out 
and  disappeared. 

The  investigations  of  Professor  Tetmajer,  of  the  Federal  Poly- 
technical  School,  at  Zurich,  developed  the  fact  that  some  German  Port- 
land cements,  when  used  in  work  exposed  for  several  years  to  the 
air,  lose  their  consistency  and  crumble. 

So  serious  had  this  danger  become  that,  only  a  few  years  ago, 
the  German  Minister  of  Public  Works  issued  a  circular  restricting 
within  narrow  limits  the  use  of  Portland  cement  in  work  exposed  to 
the  air. 

Professor  Tetmajer  found,  after  careful  examination,  that  the 
cause  of  the  disintegration  of  Portland  cement  exposed  to  the  air  is 
found  in  a  want  of  proper  preparation  of  the  materials,  particularly 
in  the  lack  of  sufficient  grinding  together  of  the  chalk  and  clay  to 
insure  the  complete  silification  of  the  lime  during  the  process  of  cal- 
cination. 

He  also  found  that  the  best  brands  of  German  Portland  cement 
which  had  withstood  the  action  of  water  for  several  years  became 
soft  on  exposure  to  air. 


AMERICAN    CEMENTS.  209 

He  says,  also,  that  "  air  especially  attacks  sharply  (hard)  burnt 
cements,  which  imbibe  a  great  deal  of  carbonic  acid,  and  the  decay 
in  water  is  caused  by  an  excess  of  matters  which  undergo  an  increase 
in  volume  by  oxidation  and  imbibing  of  water." 

What,  then,  can  justly  be  claimed  as  an  advance  in  the  art  of 
cement  fabrication  since  the  days  of  Smeaton,  one  hundred  and  forty 
years  ago  ? 

We  have  managed  to  make  a  cement  which  will  set  hard  in 
much  less  time  now  than  then,  but  at  the  expense  of  endurance  and 
this  is,  practically,  all  that  has  been  learned. 

The  cement  world  of  to-day  is  wrought  to  a  high  pitch  in  the 
matter  of  high  short-time  tests.  The  pendulum  has  swung  in  that 
direction  without  let  or  hindrance.  But  it  will  start  on  its  return 
as  soon  as  sufficient  time  has  elapsed  to  prove  beyond  question  that 
a  cement  may  test  too  high,  that  all  tests  above  the  medium  are  de- 
veloped at  the  expense  of  endurance. 

And  so  there  are  those  living  to-day  who  will  witness  the  pass- 
ing of  the  high-test  craze,  and  who  will  smile  when  they  read  of  the 
conditions  surrounding  the  testing  of  cements  during  the  latter  half 
of  the  nineteenth  century. 


210 


AMERICAN    CEMENTS. 


CHAPTER  VIII. 

THE  MANUFACTURE  OF  ROCK  CEMENT  IN  THE  UNITED  STATES 
—  VALUE  OF  PROPERTIES  —  GEOLOGICAL  AGES  OF  THE  CE- 
MENT ROCKS  IN  EUROPE  AND  THE  UNITED  STATES  —  KINDS 
OF  CEMENT  PACKAGES  IN  USE  —  THE  STURTEVANT  CRUSHERS 
AND  EMERY  MILLSTONES  ILLUSTRATED  —  TYPICAL  ROCK  CE- 
MENT AND  PORTLAND  CEMENT  WORKS  ILLUSTRATED. 

There  are  seventy-one  Rock  cement  manufactories  in  this  coun- 
try, which  are  distributed  throughout  the  several  States  in  the  fol- 
lowing order : — 


STATE. 

Number  of 
works. 

Georgia 

I 

Illinois  

2 

Indiana  and  Kentuckv      

I  C 

Kansas  .               . 

2 

Maryland  and  West  Virginia     

c 

Minnesota  

2 

New  Mexico 

New  York  ... 

2Q 

Ohio  

3 

Pennsylvania  . 

6 

Texas     

i 

Virginia      .     .                                                         . 

T. 

Wisconsin  

I 

Total    . 

71 

These  properties,  together  with  the  known  undeveloped  cement 
rock  deposits,  at  a  conservative  estimate,  are  worth  about  ten  millions 
of  dollars. 

To  describe   in   detail   all  these   cement   works   would    require 


AMERICAN    CEMENTS.  211 

many  pages.  In  fact,  an  entire  volume  could  be  written  with  very 
interesting  details,  especially  in  regard  to  the  geological  ages  in 
which  the  several  cement  rock  deposits  occur  in  this  country. 

And  it  may  be  said  in  passing  that  it  is  the  intention  of  the 
author,  in  the  preparation  of  a  future  edition,  to  take  up  this  question 
in  detail. 

For  the  purposes  of  this  work,  however,  it  will  be  briefly  noted 
that  all  of  the  cement  rock  formations  that  are  worked  in  this 
country  occur  in  the  Silurian  (both  Lower  and  Upper),  the  Devonian, 
and  the  Carboniferous  ages. 

The  author  attaches  great  significance  to  this  fact,  which  will 
be  more  apparent  to  the  reader  if  he  will  recall  the  matter  found  on 
pages  23  and  24  of  this  work,  a  thorough  understanding  of  which 
will  explain  why  the  cement  rocks  of  this  country  are  so  superior  to 
those  of  Europe,  and  especially  those  in  England,  where  all  the  Rock 
cement  produced  has  been  taken  from  the  Upper  and  Lower  Lias 
subdivisions  of  the  Jurassic  period. 

We  have  already  stated  the  uneven  character  of  those  cement 
rocks,  and  in  closing  the  subject  it  may  be  pertinent  to  add  that  in 
the  Jura-Triassic  rocks  of  this  country,  and  notably  in  the  State  of 
Connecticut,  commencing  at  New  Haven,  on  Long  Island  Sound,  and 
extending  to  Northern  Massachusetts,  having  a  length  of  1 10  miles 
and  an  average  width  of  20  miles,  these  deposits  contain  cement 
rock  formations  which  have  the  same  unfavorable  characteristics 
mentioned  in  connection  with  those  of  England. 

Three  attempts  have  been  made  to  utilize  these  rocks  for 
cement  purposes. 

In  West  River  Valley,  near  New  Haven,  two  works  were  erected 
and  operated  for  a  brief  period,  but  owing  to  the  uneven  character 
of  the  cement  rock  the  enterprises  had  to  be  abandoned. 

The  plant  at  Kensington  (noted  on  page  19)  was  one  of  the 
earliest  in  this  country. 

It  was  learned  by  the  author,  on  a  recent  visit  to  this  picturesque 
locality,  that  the  chief  incentive  to  the  erection  of  a  cement  works  at 
this  point  was  the  fact  that  the  only  hydraulic  cement  then  known 
was  produced  in  England  from  the  Jurassic  rocks,  as  stated,  and  the 
corresponding  rocks  in  this  country  were  expected  to  furnish  the 
cement  for  New  England,  at  least. 


212  AMERICAN   CEMENTS. 

The  little  factories  started  in  1818,  at  Fayetteville,  Onondaga 
County,  and  at  Williamsville,  in  Erie  County,  N.  Y.,  in  1824,  tak- 
ing their  cement  rock  from  the  Lower  Helderberg  formation,  were  at 
that  time  "  away  out  West,"  unheard  of  and  unknown. 

The  Kensington  works  had  a  fitful  existence.  The  cement  rock 
was  found  only  in  pockets  or  in  broken  fragments,  distorted  by  up- 
heavals. The  works  were  operated  spasmodically  until  the  cement 
from  the  Lower  Helderberg,  at  Rosendale,  Ulster  County,  N.  Y., 
came  into  prominence,  and,  owing  to  its  even  quality  and  general 
excellence,  it  soon  supplanted  the  Kensington  cement. 

Next  came  the  operations  near  New  Haven,  as  already  stated, 
and  this  was  the  last  of  the  attempts  to  produce  hydraulic  cement 
from  the  Jurassic  rocks  of  this  country. 

And,  as  previously  stated,  all  the  Rock  cement  manufactured  in 
this  country  is  derived  from  the  earlier  rocks,  that  were  laid  down  in 
times  of  comparative  quiet,  as  is  evidenced  by  their  even  and  uni- 
form character,  their  large  and  extended  bodies,  which  furnish,  year 
after  year,  the  same  quality  of  cement,  so  even,  in  fact,  that  the 
brands  of  all  the  seventy-one  factories  have  each  their  own  un- 
changing characteristics,  familiar  to  all  large  consumers,  each  and 
every  brand  representing  a  good,  reliable  cement. 

Were  this  not  so,  it  could  not  be  sold ;  and  a  brand  which  is 
offered  on  the  markets  year  after  year  is  evidence  of  the  most  con- 
vincing kind  that  the  quality  is  good,  for  if  it  is  not  good  it  must 
inevitably  disappear  from  the  markets  within  two  or  three  years  from 
the  time  of  its  first  appearance. 

European  writers  on  the  subject  of  cements  have  but  little  to  say 
relative  to  the  Rock  cements  of  those  countries,  except  in  terms  of 
disparagement. 

In  this  country  there  are  writers  who  gather  up  the  European 
magazine  articles  on  the  subject  of  Rock  cements  in  those  countries, 
and  by  vamping  them  up,  seem  to  expect  them  to  pass  as  sound 
American  literature. 

These  writers,  after  making  a  few  laboratory  tests,  stand  forth 
as  full-fledged  authorities  on  the  subject. 

It  is  amusing  to  note  their  studied  attempts  to  instruct  the 
American  people  as  to  the  relative  values  of  Rock  and  Portland 
cements. 


UNIVERSITY 

AMERICAN    CEMEl 


Every  line  displays  the  fact  that  their  entire  knowledge  of  the 
subject  is  gathered  from  foreign  sources. 

Therefore,  as  the  foreign  writers  treat  the  subject  of  Rock  cements 
in  those  countries,  so  also  do  their  American  imitators  treat  the  sub- 
ject of  American  Rock  cements. 

Lacking  utterly  in  technical  knowledge  and  practical  experience, 
it  never  occurs  to  these  writers  that  it  is  possible  for  the  cement 
rocks  of  Europe  and  America  to  be  quite  unlike. 

And  so  pages  are  filled  with  meaningless  platitudes  concerning 
the  uneven  qualities  of  Rock  cements  in  general,  with  the  probabili- 
ties more  than  likely  that  the  writers  never  saw  an  American  cement 
rock  deposit,  or  a  plant  for  its  manufacture. 

KINDS  OF  PACKAGES   IN  USE. 

Nearly  all  the  cement  works  of  this  country  are  located 
on  the  lines  of  railroads,  and  by  reason  of  car  shipments,  the 
expensive  wood  packages  are  fast  being  supplanted  by  cloth  and 
paper  sacks,  the  author  being  the  original  introducer  of  paper 
sacks  as  a  substitute  for  wood  packages,  about  twenty  years  /\ 
ago. 

This  innovation  proved  successful,  as  is  evidenced  by  the  fact 
that  about  4,000,000  barrels  of  cement  are  sold  annually  in  paper  sacks, 
resulting  in  a  saving  to  the  consumer  about  $650,000  annually,  this 
sum  representing  the  difference  in  the  cost  between  paper  and  wood 
packages. 

The  use  of  cloth  sacks  is  confined  mostly  to  contract  work,  where 
the  contractors  in  many  instances  own  their  sacks,  and  buy  the 
cement  in  bulk  at  mills,  sending  their  empty  sacks  to  mills  to  be 
filled. 

In  cases  where  the  manufacturers  own  the  cloth  sacks,  they 
charge  a  slight  advance  over  the  bulk  price  to  cover  wear  and  loss. 

Nearly  all  the  domestic  cement  trade  in  Europe  is  done  in  sacks, 
at  an  enormous  saving  in  cost  in  the  packages  ;  but  for  the  export 
trade  wood  packages  thus  far  seem  indispensable,  and  so  we  find  in. 
this  country  that  all  imported  cement  is  sold  in  wood  packages, 
which,  if  calculated  to  cost  twenty-two  cents  each,  the  American 
people  paid  for  the  wood  packages  containing  the  Portland  cement 
imported  during  1896,  the  sum  of  $657,711.34. 


214  AMERICAN   CEMENTS. 

CRUSHING  AND  MILLING  MACHINERY. 

The  Sturtevant  Mill  Company,  of  Boston,  Mass.,  manufactures 
cement-grinding  machinery  of  such  undoubted  merit  that  the  author 
feels  assured  a  brief  illustrated  description  of  these  most  modern 
methods  of  cement  reduction  will  prove  of  especial  interest  to  all 
cement  manufacturers,  and  perhaps  of  general  interest  to  many 
others. 


STURTEVANT  ROLL  JAW  ROCK  BREAKER  AND 
FINE  CRUSHER. 

The  Sturtevant  Roll  Jaw  Crusher  is  a  peculiar  machine,  and  is 
capable  of  fine  work ;  it  takes  in  rocks  of  large  size  and  reduces  them 
at  once  to  gravel  and  sand,  thus  doing  the  work  of  a  large  jaw 
crusher  and  one  or  two  sets  of  rolls  without  any  auxiliary  machinery. 

The  cut  shows  a  6  by  1 6  roll  jaw  crusher;  the  toggles  are  like 
those  of  other  crushers,  but  the  long  lever  roll  jaw  gives  immense 
power,  and  as  its  curved  jaw  face  makes  a  perfect  roll,  it  crushes 
without  any  rubbing  action  whatever. 

The  roll  jaw  passes  over  the  rock  being  crushed,  which  then 
drops  out  without  any  tendency  to  clog.  The  product  is  as  regular 
in  size  as  that  from  rolls. 


AMERICAN    CEMENTS.  215 

This  machine  crushes  Portland  clinker,  or  any  hard  rock,  to 
such  fineness  as  may  be  suitable  for  fine  reduction  in  mills  or  mill- 
stones. 

The  Roll  Jaw  Crusher  requires  little  power,  and  is  a  solid,  well- 
made,  and  durable  machine. 

This  crusher  will  take  Portland  Cement  clinker  just  as  it  comes 
from  the  kiln  and  at  a  single  operation  will  reduce  it  fine  enough  for 
milling. 

The  6  by  1 6  breaker  weighs  about  7  tons  ;  the  heaviest  piece 
weighs  less  than  3,000  Ibs.  and  the  machine  will  run  with  10  h.  p. 
under  ordinary  conditions.  It  will  crush  3  tons  per  hour  of  Port- 
land clinker,  or  any  hard,  dry  material,  such  as  granite,  limestone, 
etc.,  when  set  to  X  'm-  opening,  and  about  half  of  such  product  is 
Y%  in.  and  finer. 

These  machines  are  made  in  larger  and  smaller  sizes.  The 
crushing  motion  is  a  true  roll  without  any  grinding  action  whatever, 
and  this  ensures  great  durability  to  the  jaws  and  the  minimum  cost 
of  running. 

Rock  Emery  Millstones  may  be  seen  running  in  many  of  the 
Rock  and  Portland  cement  works  of  this  country  and  England. 

They  are  made  in  all  sizes  and  to  fit  any  mill  frame.  As  is 
shown  clearly  in  the  cut,  the  skirt  of  this  millstone  is  formed  of  large 
blocks  of  emery,  set  in  a  metal  filling  that  holds  them  with  ample 
strength.  The  center  of  the  millstone  is  made  from  a  single  block 
of  Esopus  stone,  and  the  furrows  are  of  sandstone  set  on  edge. 

This  combination  of  materials  forms  a  grinder  that  is  not  in- 
jured by  heat,  and  consequently,  Rock  Emery  Millstones  may  be  run 
at  high  speed. 

The  extraordinary  hardness  and  cutting  properties  of  emery 
are  so  well  known  that  it  would  be  surprising  if  it  did  not  form  the 
hardest,  strongest,  and  most  abrasive  millstone  face  that  can  be 
made. 

Emery  millstones  are  capable  of  doing  fine  work,  and  they  are 
rapid  grinders.  They  require  to  be  fed  with  finely  crushed  material, 
if  it  is  hard,  and  it  should  not  be  larger  than  grains  of  wheat. 

The  Emery  face  should  be  dressed  occasionally.  In  careful 
hands  these  millstones  grind  fast  and  fine,  and  last  long. 

The  Sturtevant  Emery  42  in.  Complete  Mills  are  grinding,  on  an 


216  AMERICAN   CEMENTS. 

average,  5  to  6  bbls.  of  finished  Portland  cement  per  hour,  when 
working  on  properly  crushed  clinker,  93  to  95  per  cent,  of  the  prod- 
uct passing  100  mesh. 

The  same  machines  are  grinding  steadily  from  18  to  20  bbls. 
per  hour  of  Rock  cement  95  per  cent,  fine,  and  are  also  turning  out 
from  i  j£  to  2  tons  per  hour  of  raw  Portland  material. 

Emery  stones  often  wear  from  three  to  five  years  on  Portland 
cement,  and  will  average  to  grind  under  the  same  conditions  at  least 
one  third  more  than  the  best  French  buhrs.  They  will  run  from 


STURTEVANT    ROCK    EMERY    MILL    STONE. 
Trade  Mark. 

3  to  4  weeks  on  Portland  cement  without  being  taken  up  for  dressing, 
and  the  dressing  which  they  require  at  the  end  of  that  time  is  of  the 
simplest  character. 

These  machines  take  about  15  to  1 8  h.  p.  to  drive,  and  will  run 
smoothly  and  without  vibration  on  a  good  mill  floor,  thus  requiring 
no  expensive  foundation. 

These  42  in.  mills  are  heavy  and  substantial,  weighing  fully 
6,000  Ibs.  complete,  and  are  constructed  to  run  at  high  speed  (which 


AMERICAN    CEMENTS.  217 

does  not  injure  emery  stones)  and  with  the  least  possible  vibration, 
thus  being  able  to  do  the  very  finest  grinding. 

The  bedstone  is  bolted  in  place,  and  cannot  be  got  in  wrong, 
and  the  hand-wheel  adjustment  raises  and  lowers  this  stone  with  ab- 
solute accuracy  upon  the  runner,  against  which  it  presses  elastically 
(with  as  much  force  as  may  be  desired),  and  is  thus  able  to  release 
quickly  bolts,  nuts,  or  any  hard  foreign  material  that  may,  by  acci- 
dent, get  between  the  stones. 

The  running  stone  is  rigidly  fixed  to  the  very  short  and  large 
shaft,  and  has  no  adjustments.  By  this  arrangement  the  stones  are 


STURTEVANT   ROCK    EMERY   MILL. 

always  together  in  perfect  alignment,  and  cannot  be  carelessly  set  or 
run;  i.  e.,  it  requires  no  expert  to  keep  the  mill  in  running  balance, 
as  is  the  case  with  cock-head  mills,  and  these  mills  are  much  finer 
grinders.  Indeed,  there  is  no  mill  made  that  can  compete  with  this 
for  fine  or  rapid  work. 

The  frame  is  built  to  run  at  high  speed,  and,  if  provided  with 
emery  stones  (which  do  not  crack  when  hot),  can  do  more  work 
than  other  mills,  and  reduce  materials  heretofore  supposed  to  be  un- 
grindable.  The  bearings  are  bronze,  and  all  run  in  oil.  The  remark- 


218  AMERICAN    CEMENTS. 

able  simplicity  of  this  horizontal  mill,  and  its  great  solidity,  is  shown 
in  the  cut.  It  is  made  to  last,  and  to  give  no  trouble.  With  Rock 
Emery  Millstones  it  can  grind  rapidly  and  economically  a  long  list 
of  substances  that  would  rapidly  dull  the  best  French  buhrs. 

CEMENT  MANUFACTORIES. 

While  in  these  pages  we  cannot  undertake  to  describe  all  the 
existing  cement  works,  we  have  selected  a  few  which  may  be  con- 
sidered as  fairly  representative. 

They  are  typical  works,  and  embody  about  all  the  most  advanced 
methods  employed  in  manufacture. 

They  are  chosen  with  a  view  to  representing  the  types  which 
are  prevalent  in  the  leading  districts  of  Rock  cement  production. 

The  Portland  cement  works  represented  may  be  said  to  stand 
in  the  front  rank  of  that  class  of  manufactories  in  this  country,  and 
is  given  that  our  readers  may  get  a  clear  idea  of  the  prevailing 
methods  employed  in  the  production  of  high  grade  artificial  cements. 

THE  MANUFACTURE  OF  UTICA  CEMENT. 

The  works  of  the  Utica  Hydraulic  Cement  Company,  of  Utica, 
111.,  consist  of  a  plant  capable  of  producing  2,000  barrels  of  finished 
cement  per  day. 

The  company  owns  1,500  acres  of  land,  containing  the  cement 
rock,  the  latter  being  about  7  ft.  in  thickness,  which  belongs  in  the 
calciferous  epoch  of  the  Lower  Silurian  age. 

The  company  usually  mines  the  cement  rock,  although  having 
open  quarries  as  well. 

The  drilling  is  done  with  power  drills,  driven  by  compressed  air. 

The  chambers  in  the  mine  are  about  40  ft.  square,  26  in  number, 
all  connecting  with  a  main  gallery. 

The  kilns  are  of  the  iron  type,  and  in  operation  are  continuous. 

The  mill  is  equipped  with  a  double  Corliss  engine  of  300  H.  P., 
which  drives  all  the  machinery. 

The  material  as  it  comes  from  the  kilns  is  deposited  into  a  No. 
5  Gates  crusher,  which  crushes  it  to  the  size  of  a  walnut,  and  from 
the  crusher  it  passes  into  two  roller  or  pan  pulverizers,  from  which 
the  cement  is  elevated,  coming  down  over  three  sliding  screens,  from 
which  is  obtained  60  per  cent,  of  finished  cement. 


THE   CLARK    MILLS,    UTICA,    ILL. 


AMERICAN    CEMENTS.  223 

The  tailings  from  the  sliding  screens  are  carried  to  a  battery  of 
millstones  consisting  of  four  run  of  30  in.  vertical  buhrs,  and  two 
run  of  42  in.  horizontal  ernery  stones,  where  the  grinding  is  com- 
pleted. 

The  finished  cement  from  the  rollers  and  the  millstones  meet  in 
a  general  conveyor,  where  a  thorough  mixing  takes  place  before  the 
cement  reaches  the  packing  room  or  storage  rooms. 

The  company  enjoys  most  excellent  facilities  for  shipping  by 
rail,  and  has  an  immense  storage  capacity  in  warehouses  adjoining 
the  railroad  tracks. 

On  page  20  a  brief  history  of  these  works  will  be  found. 

This  company  has  recently  come  into  possession  of  the  large 
and  important  Rock  cement  works  at  La  Salle,  111.,  where  the  "  Black 
Ball "  brand  of  Utica  cement  is  manufactured.  A  notice  of  these 
works  will  be  found  on  page  22. 

CUMMINGS  CEMENT,  ITS  MANUFACTURE. 

The  works  of  The  Cummings  Cement  Company  are  situated  at 
Cummingston,  New  York,  on  the  Batavia  and  Tonawanda  branch 
of  the  New  York  Central  and  Hudson  River  Railroad  at  its  intersec- 
tion with  the  West  Shore  Railroad,  twenty  miles  northeast  of  Buf- 
falo, N.  Y.  Post-office,  Akron,  N.  Y. 

The  cement  rock  of  this  locality  belongs  to  the  Lower  Helder- 
berg  period  of  the  Upper  Silurian  age.  The  color  of  the  rock  is  a 
dark  blue,  the  fracture  conchoidal,  and  the  texture  exceedingly  fine 
and  uniform,  showing  the  clay  and  carbonate  of  lime  to  be  intimately 
commingled  in  the  rock. 

The  company  owns  575  acres  of  land  containing  this  material, 
which  is  sufficient  to  produce  63,500,000  barrels  of  the  manufactured 
cement. 

The  deposit  is  from  7  to  8  ft.  in  thickness,  and  the  strata,  which 
are  remarkably  uniform  in  character,  lie  horizontally  underneath  a 
rock  capping  of  about  60  ft.  in  thickness,  the  lower  1 5  ft.  of  which 
consists  of  hydraulic  limestone,  the  rock  above  this  being  black  flint. 

The  cement  rock  is  mined  by  drifts  which  widen  into  chambers 
from  80  to  1 50  ft.  in  width,  pillars  of  cement  rock  being  left  occa- 
sionally for  the  support  of  the  roof. 

The  drifts  are  started  in  the  perpendicular  ledge  facing  the 


224  AMERICAN   CEMENTS. 

plant,  and  are  nearly  on  a  level  with  the  tops  of  the  kilns,  which 
stand  about  75  ft.  away  from  the  face  of  the  ledge. 

Power  drills  are  used  in  the  mine  and  are  driven  by  compressed 
air,  and  the  working  face  of  the  cement  rock  strata  is  three  fourths 
of  a  mile  in  extent. 

After  the  rock  is  blasted  out,  it  is  broken  into  suitable  sizes,  and 
is  then  loaded  into  tram  cars  and  hauled  to  the  mouth  of  the  tunnel 
facing  the  plant,  where  the  cars  are  attached  to  cables  and  are  drawn 
upon  the  kilns. 

Layers  of  coal  are  spread  over  the  cement  rock  in  the  cupolas 
of  the  kilns,  and  the  rock  in  the  cars  is  dumped  thereon,  when  an- 
other layer  of  coal  is  applied;  and  thus  the  kilns  are  kept  filled 
during  the  day,  while  the  calcined  cement  rock  is  removed  from  the 
base  of  the  kilns,  where  it  is  shoveled  directly  into  cars,  and  thence 
hauled  by  cable  into  the  second  story  of  the  mill  on  an  incline  track. 

The  calcining  department  consists  of  8  kilns,  the  cupolas  of 
which  measure  9  by  22  ft.  in  surface  area,  and  9  kilns  with  round 
cupolas  9  ft.  in  diameter,  all  being  34  ft.  in  height. 

The  total  surface  area  of  the  cupolas  in  the  1 7  kilns  is  equiva- 
lent to  34  kilns  with  round  cupolas  9  ft.  in  diameter,  or  28  kilns 
having  round  cupolas  10  ft.  in  diameter. 

During  the  calcination,  which  is  done  at  a  white  heat,  a  con- 
siderable proportion  of  the  cement  rock  becomes  clinkered,  and  the 
latter  is  exceedingly  hard  and  heavy,  and  is  very  difficult  to  reduce  to 
powder ;  but  as  it  possesses  hydraulic  properties  to  a  remarkable 
degree,  it  is  not  rejected,  as  is  customary  at  manufactories  where  the 
clinkered  portion  is  light  and  friable. 

But  the  machinery  in  common  use  throughout  the  country  for 
grinding  ordinary  Rock  cement  was  found  entirely  inadequate.  In 
fact,  such  machinery  could  not  handle  this  material  without  being 
soon  broken  and  destroyed. 

It  was  necessary,  therefore,  owing  to  the  extreme  difficulty 
experienced  in  reducing  the  product  to  a  fine  powder,  to  devise 
special  machinery  for  the  purpose  of  overcoming  the  extraordinarily 
abrasive  character  of  this  material. 

To  that  end  a  general  system  of  gradual  reduction  was  employed, 
which  finally  proved  adequate. 

It  consists  of  four  different  systems.     First,  Sturtevant  crushers; 


AMERICAN    CEMENTS.  227 

second,  Cummings  pulverizers ;  third,  ten  run  of  42  in.  underrunner 
millstones  faced  with  chilled  iron  plates  ;  fourth,  ten  run  of  42  in. 
hard  Esopus  underrunner  millstones. 

The  material,  as  it  is  conveyed  from  one  to  another  of  these 
systems,  is  made  to  pass  over  screens  whereby  such  material  as  has 
been  reduced  to  proper  fineness  is  separated  from  the  mass  and  is 
spouted  to  a  general  conveyor,  which  finally  receives  the  product 
from  all  of  the  systems  and  conveys  it  to  the  packing  house. 

Each  system,  while  it  finishes  a  portion  of  the  material,  reduces 
the  sizes  of  the  unground  portion  to  such  a  degree  that  the  material 
which  is  fed  to  the  fourth  system  is  broken  and  worn  down  to  the 
size  of  kernels  of  wheat,  and  is  exceedingly  hard  to  reduce. 

The  power  necessary  to  drive  this  machinery  consists  of  a 
battery  of  seven  tubular  boilers  5  ft.  in  diameter  and  16  ft.  long,  and 
a  pair  of  engines  whose  cylinders  are  24  by  48  ins.,  connected  to 
a  single  shaft  which  carries  a  balance  wheel  20  ft.  in  diameter,  with  a 
face  suitable  for  a  36  in.  heavy  belt,  which,  at  a  speed  of  3,900  ft. 
per  minute,  drives  the  entire  machinery. 

There  is  also  an  auxiliary  plant  joining  the  main  mill,  consisting 
of  two  boilers  of  6  ft.  diameter  and  18  ft.  long,  and  an  18  by  24  in. 
engine,  and  two  roller  pulverizers  with  the  necessary  equipment  for 
use  in  emergencies.  This  power  is  also  used  for  handling  coal  cars 
on  the  trestles  and  dumps. 

The  cooper  shop  is  connected  to  the  works  by  a  covered  in- 
clined track  400  ft.  long,  by  which  the  empty  barrels  are  rolled  into 
the  packing  department. 

There  are  5,400  ft.  of  railroad  track  in  and  about  the  works,  the 
latter  covering  3^  acres  of  ground,  and  thirty  cars  can  be  loaded 
from  the  spacious  warehouses  without  the  necessity  of  moving  a  car. 

In  the  mines  there  are  8,000  ft.  of  tramway  track,  to  which  con- 
stant additions  are  being  made  as  the  tunnel  is  extended  by  the 
removal  of  the  rock. 

The  testing  department  is  equipped  with  the  most  approved 
machinery  for  the  purpose,  and  test  sheets  are  furnished  with  each 
shipment  of  cement,  and  are  mailed  to  the  purchaser.  These  test 
sheets  show  the  quality  of  the  cement  as  guaranteed  by  the  com- 
pany. 

The  "  Cummings"  brand  of  cement  was  established  in  1854  by 


228  AMERICAN   CEMENTS. 

H.  Cummings  &  Sons,  at  Akron,  N.  Y. ;  the  head  of  this  firm 
being  the  father  of  the  president,  and  treasurer  of  the  present  com- 
pany, and  grandfather  of  the  secretary  and  vice-president. 

From  the  date  given  until  Jan.  i,  1898,  the  number  of  barrels 
of  cement  bearing  the  name  of  "  Cummings  "  has  reached  the  total 
of  8,000,000  barrels. 

This  company  also  manufactures  Portland  cement  in  large 
quantities,  which  is  sold  under  the  following  brands,  namely :  — 

"  Storm  King,"  "  Uncle  Sam,"  and  "  Roman  Rock."  The  natural 
rock  cement  produced  by  this  company  bears  the  "  Obelisk  "  brand. 
These  brands  are  shipped  to  nearly  every  State  in  the  Union. 

The  Western  Union  Telegraph  wires  enter  the  office  of  the  com- 
pany at  the  works,  Akron,  New  York  ;  main  office,  Buffalo,  New 
York ;  New  England  office,  Stamford,  Conn. 

Its  officers  are  :  Uriah  Cummings,  president;  Ray  P.  Cummings, 
vice-president;  Homer  S.  Cummings,  secretary ;  and  Palmer  Cum- 
mings, treasurer  and  general  manager. 

THE  MANUFACTURE  OF  LOUISVILLE  CEMENT. 

The  discoverer  of  the  Argillo  magnesian  limestone  formation 
under  the  falls  of  the  Ohio  River,  from  which  Louisville  cement  was 
first  made,  is  unknown.  John  Hulme  &  Co.  operated  a  grain  mill 
on  the  banks  of  the  Ohio,  in  which  cement  was  manufactured  in 
limited  quantities,  prior  to  1829.  Fragments  of  stone  in  the  river 
exposed  in  low  water  were  collected,  burned  in  improvised  kilns, 
then  cracked  in  small  pieces  and  ground  in  the  Hulme  Mill,  between 
stones  driven  by  a  water  wheel  in  the  river.  "  All  was  grist "  that 
came  to  Hulme  &  Co.  Persons  desiring  cement  took  their  turn  at 
the  mill  with  farmers  having  grain  to  grind. 

To  supply  cement  for  use  on  the  locks  of  the  Louisville  and  Port- 
land Canal,  in  process  of  construction  by  the  United  States  Govern- 
ment in  1829,  the  first  permanent  kilns  for  calcining  cement  stone 
were  built.  From  this  time  the  manufacture  of  Louisville  cement 
has  continuously  increased.  For  many  years  the  mills  located  on  the 
Ohio  River  enjoyed  a  monopoly  of  the  cement  business,  the  impres- 
sion generally  prevailing  that  cement  stone  was  to  be  found  only  in 
the  bed  of  the  Ohio  River,  and,  therefore,  inaccessible  except  in  the 
shallow  water  of  the  rapids.  Increasing  demand  and  large  profit 


THE    CUMMINGS    CEMENT    COMPANY,    AKRON,    N.   Y. 


THE   CUMMINGS    CEMENT    COMPANY,    AKRON,    N.    Y. 


(  UNIVERSITY  ) 


THE    CUMMINGS    CEMENT    COMPANY,   AKRON,   N.   Y. 


AMERICAN    CEMENTS. 


235 


realized  from  the  mills  on  the  river  stimulated  investigation  on  the 
part  of  others,  who,  carefully  tracing  the  strata  of  rock,  then  ex- 
posed to  view  only  in  the  Ohio  River,  for  some  miles  north  of  the 
river,  in  1866  located  a  small  plant,  with  a  daily  capacity  of  200  barrels, 
on  the  line  of  the  J.  M.  &  I.  R.  R.,  in  Indiana.  The  advantages  of 
railroad  transportation  and  economical  quarries,  which  could  be  oper- 
ated without  the  interruption  and  consequent  expense  to  which  the 
river  quarries  were  subjected  by  high  water,  were  too  great  to  be 
long  enjoyed  by  the  pioneer  inland  mill  without  competition  under 
normal  conditions. 

The  destruction  in  the  South,  incident  to  the  Civil  War,  to  be 
repaired,  the  extension  of  old  and  the  projection  of  new  railroads, 
and  other  enterprises  in  the  North  and  West,  created  a  demand  in 
excess  of  the  capacity  of  the  then  existing  mills.  Others  followed 
at  intervals,  until  the  works  in  the  Louisville  group,  devoted  exclu- 
sively to  the  manufacture  of  Louisville  cement,  consisting  of  thirteen 
mills,  have  a  combined  capacity  of  15,000  barrels  per  day,  and  are 
now  the  largest  and  best-equipped  works  in  the  world  for  the  produc- 
tion of  natural  cement.  From  a  few  thousand  barrels  produced  by 
the  original  mill  on  the  river  for  local  consumption,  the  annual  pro- 
duction of  the  thirteen  mills  has  exceeded  2,100,000  barrels,  or 
about  one  fourth  of  the  natural  cement  manufactured  in  the  United 
States,  and  if  necessary  could  be  increased  without  enlargement  of 
the  present  plants,  the  capacity  now  being  greatly  in  excess  of  any 
consumption  of  cement  which  may  reasonably  be  expected  for  many 
years  to  come. 

The  stone  from  which  Louisville  cement  is  made  is  peculiar  to 
a  small  area,  only  a  few  miles  wide,  extending  north  of  the  Ohio 
River  about  fifteen  miles,  and  is  not  found  elsewhere.  It  is  generally 
covered  with  earth,  but  occasionally  a  stratum  of  limestone  intervenes 
between  the  earth  and  cement  stone.  Where  this  occurs  the  stone  is 
mined ;  where  covered  by  a  few  feet  of  earth  only  it  is  obtained  by 
open  quarrying.  The  illustrations,  given  on  another  page,  of  the  en- 
trance to  the  tunnel  and  the  open  mine  are  typical,  and  show  the  two 
methods  of  obtaining  supplies  of  stone  for  the  manufacture  of  cement 
at  all  of  the  mills  in  the  Louisville  district. 

The  formation  of  cement  stone  is  generally  in  horizontal  strata, 
dipping  slightly  to  the  southwest,  nearly  uniform  in  size  and  color, 


236  AMERICAN    CEMENTS. 

and  varies  from  10  to  16  ft.  in  depth.  The  open  mine  shown  is 
about  900  ft.  long,  with  a  face  of  16  ft.,  and  furnishes  material  for 
3,500  barrels  of  cement  daily. 

In  the  preparation  of  stone  for  the  manufacture  of  Louisville 
cement,  no  admixture  of  the  different  strata  is  necessary,  the  forma- 
tion being  uniform  in  all  essential  characteristics.  The  liability  of  an 
inferior  product,  due  to  an  improper  mixture,  is  eliminated ;  there 
being  no  material  to  be  obtained  more  cheaply  than  the  best,  there  is 
no  incentive  to  the  manufacturer,  in  seasons  of  great  demand,  to 
increase  his  product  at  the  expense  of  quality. 

The  process  of  manufacture,  from  the  removal  of  the  stone  from 
its  bed  to  the  finished  product,  being  substantially  the  same  in  all  of 
the  works  in  the  Louisville  district,  a  description  of  the  process  at 
one  of  the  thirteen  plants  will  suffice  for  all. 

At  the  works  described,  stone  is  obtained  from  the  open  quarry 
in  the  usual  manner,  by  means  of  steam  or  compressed  air  drills  and 
high  explosives.  It  is  loaded  in  boxes  of  about  3  tons  capacity, 
which  are  hoisted  by  a  10  ton  locomotive  crane,  and  deposited  on 
the  trucks  of  the  quarry  train.  The  trains  of  stone  are  hauled  by 
a  locomotive  to  the  crusher  house,  there  the  stone  is  reduced  by  a 
Blake  crusher  of  400  barrels  per  hour  capacity  into  pieces  of  three 
uniform  sizes  for  calcination.  By  means  of  screens  and  chutes,  each 
size  is  discharged  into  cars  in  which  it  is  hauled  to  the  kilns. 

The  kilns  are  of  the  usual  pattern,  cylindrical  in  shape,  about 
45  ft.  high  and  16  ft.  in  diameter,  made  of  iron,  lined  with  fire-brick. 
The  stone  is  charged  into  the  kilns  from  bottom  dumping  cars  on  the 
track  which  surmounts  the  kilns.  By  means  of  a  coaling  machine 
the  proper  amount  of  coal  is  accurately  measured  and  charged  into 
the  kilns  in  alternate  layers  with  stone.  By  the  use  of  this  machin- 
ery the  personal  factor  is  eliminated,  and  a  more  evenly  calcined 
product  secured,  than  is  possible  by  the  old  method  of  leaving  the 
amount  of  coal  necessary  to  the  judgment  of  the  burner.  The  kilns 
are  continuous,  after  being  kindled  in  the  spring,  until  operations 
cease  for  the  winter. 

The  calcined  stone  is  drawn  from  openings  near  the  base  of  the 
kilns,  from  which  it  falls  by  gravity  over  iron  aprons  into  cars  on  a 
track  below.  These  cars  are  hoisted  into  the  mill,  and  dumped  upon 
an  inclined  platform,  on  which  the  material  descends  automatically 


THE    LOUISVILLE   CEMENT    COMPANY,    LOUISVILLE,   KY. 


AMERICAN    CEMENTS.  239 

to  the  coarse  crushers.  While  upon  this  platform,  the  imperfectly 
burned  material  is  carefully  culled  out,  thrown  aside  to  be  reburned ; 
in  this  connection  it  maybe  interesting  to  note  that  everburning  does 
not  impair  the  quality  of  Louisville  cement,  the  effect  of  everburning 
being  to  diminish  its  activity  only,  without  impairing  its  hydraulic 
energy. 

A  battery  of  three  250  H.  P.  Babcock  &  Wilcox  boilers  supply 
steam  to  two  Corliss  engines,  which  furnish  motive  power  to  the  grind- 
ing machinery  in  the  mill  proper,  consisting  of  seven  cast-iron  coarse 
crushers,  twelve  fine  crushers,  and  ten  pairs  of  emery  stones  54  ins. 
in  diameter. 

The  process  of  reducing  the  calcined  stone,  as  it  comes  from 
the  kilns,  to  powder  begins  in  the  coarse  crushers,  from  which  it 
passes  in  pieces  about  the  size  of  a  hazelnut  to  the  fine  crushers, 
which  reduce  it  in  varying  degrees  from  particles  about  the  size  of 
wheat  to  fine  powder,  the  coarser  particles  passing  on  to  the  emery 
stones. 

By  means  of  a  system  of  elevators  and  screens  the  material  is 
screened  as  it  comes  from  each  crusher,  and  the  various  streams  of 
finished  product  from  the  crushers  and  buhrs  are  carried  through  a 
common  spiral  conveyor  to  the  packing  room.  By  this  arrangement 
a  thorough  mixture  of  them  all  is  effected,  and  each  package  of 
cement  contains  material  from  6  to  12  kilns,  thus  securing  uniformity 
of  product  not  otherwise  obtainable. 

The  entire  process  of  manufacture  from  the  quarry  to  the  pack- 
ing room,  where  the  cement  is  packed  for  shipment,  is  under  the  su- 
pervision of  competent  men.  Samples  are  taken  at  frequent  inter- 
vals during  the  day,  which  are  carefully  tested  for  fineness,  time  of 
setting,  and  tensile  strength. 

In  the  transportation  of  the  stone  from  the  quarry,  and  of  the 
daily  product  of  3,500  barrels  of  265  Ibs.  net  from  the  mill  to  the 
tracks  of  the  P.  C.  C.  &  St.  L.  R.  R.,  several  locomotives  and  a 
large  number  of  cars  are  employed. 

In  connection  with  this  work  is  a  machine  shop,  a  cooper  shop, 
a  store,  88  residences  for  operatives,  and  storehouses  capable  of 
storing  80,000  barrels  of  cement. 

In  the  machine  shop  are  facilities  for  making  repairs  and  build- 
ing new  machinery.  As  an  indication  of  the  completeness  of  this 


240  AMERICAN   CEMENTS. 

shop,  may  mention  one  of  the  large  Corliss  engines  used  in  this 
works  was  built  here. 

The  cooper  shop  is  fitted  with  the  latest  trussing,  setting  up, 
and  crozing  machinery,  capable  of  producing  2,000  barrels  per  day, 
when  operated  to  its  full  capacity.  In  connection  with  this  shop  are 
ample  storehouses  for  staves,  heading,  and  other  supplies.  Here,  as 
in  every  department  of  this  works,  nothing  is  done  by  hand  that  can 
be  done  as  well  by  machinery. 

Methods  of  manufacture  being  substantially  the  same  in  all  of 
the  works  in  the  Louisville  district,  the  variation  from  a  uniform 
product  is  reduced  to  a  minimum,  as  the  stone  varies  only  slightly, 
either  in  its  physical  properties  or  chemical  constituents.  The  widest 
variation  is  in  color,  chiefly  due  to  the  presence,  in  varying  quanti- 
ties, of  oxide  of  iron,  which  has  no  effect  other  than  to  deepen  the 
color  of  the  cement. 

The  consumption  of  Louisville  cement  is  not  confined  to  re- 
stricted' territory.  It  is  shipped  from  Ontario  to  Florida,  and  from 
the  Atlantic  coast  to  the  Rocky  Mountains.  It  is  employed  in  piers 
of  railroad  bridges  spanning  our  great  waterways ;  in  reservoirs 
containing  water  supply  of  our  Western  cities;  modern  city  road- 
ways and  pavements  are  supported  on  concrete  foundations  made  of 
it;  currency  and  valuables  are  secured  in  safes  and  vaults  rendered 
fire-proof  by  the  use  of  it.  For  building  purposes  it  has  largely 
superseded  lime,  and  its  worth  as  a  building  material  is  receiving 
the  attention  it  has  long  deserved. 

A  brief  notice  of  Louisville  cement  is  given  on  page  19. 

THE  LAWRENCE  CEMENT  COMPANY. 

In  1823,  while  building  the  Delaware  &  Hudson  Canal  near 
the  village  of  Rosendale,  Ulster  County,  N.  Y.,  the  fact  was  dis- 
covered that  the  dark-blue  limestone  rock  through  which  the  canal 
was  being  excavated  possessed  hydraulic  properties,  and,  upon 
proper  calcination,  would  produce  a  powerful  hydraulic  cement. 
About  ten  years  later,  or  in  1832,  Watson  E.  Lawrence  built  a  few 
small  kilns,  opened  a  mill,  and  began  the  manufacture  of  the  "  Law- 
rence "  brand  of  Rosendale  cement  on  the  banks  of  Rondout  Creek, 
not  far  from  the  village  of  Rosendale.  This  mill,  which  has  long 
since  been  closed,  was  operated  by  water  power  from  the  creek,  and 


THE   LOUISVILLE    CEMENT    COMPANY,    LOUISVILLE,    KY. 


AMERICAN    CEMENTS.  243 

was  capable  of  producing  20  barrels  of  cement  per  day.  The  growth 
of  the  company's  works  since  the  opening  of  the  first  mill  has  been 
in  proportion  to  the  enormous  growth  of  the  Rosendale  cement  in- 
dustry in  this  country.  The  present  mills  of  the  Lawrence  Cement 
Company  can  produce  5,300  barrels  of  cement  per  day  and  about 
1,166,000  barrels  per  year,  or  about  one  third  of  the  Rosendale  ce- 
ment manufactured  in  Ulster  County,  and  about  one  eighth  of  the 
total  amount  manufactured  in  the  United  States. 

Briefly  summarized,  the  company's  works  consist  of  three  mills, 
located  at  Binnewater,  Eddyville,  and  Esopus.  The  mill  at  Esopus, 
although  in  full  working  order,  is  not  being  operated,  but  the  other 
two  are  grinding  the  rock  from  66  kilns,  and  producing,  as  before 
stated,  5,300  barrels  of  cement  per  day.  The  respective  capacities 
of  the  two  mills  in  operation  are,  2,500  barrels  and  2,800  barrels  of 
cement  per  day.  In  connection  with  each  of  the  cement  mills  proper 
are  storehouses,  cooper-shops,  repair  shops,  power  houses,  and  offices, 
and,  in  addition,  all  the  cableways,  tramways,  and  hoisting  apparatus 
necessary  in  handling  both  the  cement  rock  and  the  barrels  and  bags 
of  manufactured  cement. 

The  source  from  which  the  Lawrence  Cement  Company  derives 
its  supply  of  cement  rock  is  the  well-known  tentaculate  of  water 
limestone  belonging  to  the  great  natural  cement  rock  formation 
extending  along  the  Appalachian  Mountains  from  Vermont  to 
Virginia.  In  Ulster  County  the  deposits  are  mostly  found  within 
the  limits  of  a  narrow  belt,  scarcely  a  mile  wide,  skirting  the  base 
of  the  Shawangunk  Mountains,  along  the  line  of  the  Delaware  & 
Hudson  Canal,  in  the  valley  of  Rondout  Creek.  Owing  to  a  suc- 
cession of  upheavals,  of  which  the  whole  region  exhibits  remark- 
able evidences,  the  bed,  or  strata,  of  cement  rock  is  found  in  almost 
every  conceivable  inclination  to  the  horizon,  but  ordinarily  dipping  in 
a  greater  or  less  degree  to  the  northwest  or  southeast.  The  useful 
effect  of  these  upheavals  has  been  to  raise  into  accessible  and  con- 
venient positions  the  cement  rock  which  would  otherwise  have  been 
buried  beyond  practicable  reach  for  manufacture.  As  it  is,  the  out- 
cropping strata  are  worked  by  open  quarrying. 

The  rock  used  in  the  manufacture  of  "  Hoffman  "  Rosendale 
cement  is  taken  from  two  beds  separated  by  a  sandstone  rock 
known  as  the  "  middle  rock."  The  upper  of  these  beds  is  known 


244  AMERICAN    CEMENTS. 

as  the  "  light  rock,"  and  the  lower  as  the  "  dark  rock,"  and  the  two 
are  mixed  together  in  the  proportion  found  to  give  the  best  results. 
These  quarries  are  carried  into  the  hills  to  various  depths,  follow- 
ing always  the  layer  of  cement  rock.  In  the  quarrying,  power  drills 
are  used,  and  the  explosives  employed  are  dynamite  and  black  pow- 
der. After  blasting,  the  rock  is  broken  into  pieces  varying  from  the 
size  of  an  orange  to  that  of  a  football,  loaded  into  tram  cars  and 
taken  to  the  kilns  for  burning.  The  appearance  of  a  quarry  after 
the  excavation  of  the  cement  rock  is  very  clearly  shown  in  the  illus- 
tration given  on  page  249,  titled  "  Hoffman "  Rosendale.  Here  it 
will  be  seen  that  all  of  the  cement  rock  in  sight,  excepting  the  pil- 
lars left  to  support  the  roof,  has  been  excavated,  and  quarrying  op- 
erations are  now  being  carried  on  further  in  to  the  left  of  the  view. 

In  describing  the  process  of  manufacture  of  "  Hoffman  "  Rosen- 
dale  cement,  from  the  blasting  of  the  rock  to  the  labeling  of  the 
barrels  of  cement  ready  for  shipment, «the  works  at  Binne water  have 
been  selected  for  illustration.  This  may  be  taken  as  a  typical  plant, 
and  a  description  of  the  process  of  manufacture  as  carried  out  here 
will  apply  equally  well,  except  in  minor  details,  to  any  of  the  com- 
pany's other  plants.  At  the  Binnewater  plant  the  quarries  are  located 
in  the  ridge  directly  to  the  rear  of  the  mills.  This  location  is  un- 
usually favorable,  however,  and  for  the  other  mills  the  rock  has  for 
the  most  part  to  be  transported  a  considerable  distance  by  tram- 
way. In  several  instances,  also,  the  kilns  are  located  at  some  dis- 
tance from  the  mills,  and  the  burned  rock  has  to  be  conveyed  to  the 
mills  in  tram  cars.  After  the  excavation  and  breaking  of  the  rock  it 
is  conveyed  to  the  kilns,  and,  by  means  of  a  track  passing  over  their 
tops,  is  dumped  directly  from  the  cars  to  convenient  points  for  charg- 
ing them.  In  the  view,  showing  the  Binnewater  plant,  the  location 
of  the  kilns  to  the  rear  of  the  mills  is  shown,  and  in  another  view 
are  shown  the  kilns  at  Hickory  Bush  supplying  the  Eddyville  mill. 

The  process  of  calcination  is  very  simple,  in  as  far  as  not 
requiring  an  elaborate  apparatus  is  concerned,  but  it  requires  con- 
stant watchfulness  and  care,  a  thorough  knowledge  of  the  effects  of 
the  temperature  and  of  the  velocity  and  direction  of  the  wind,  and 
perfect  familiarity  with  the  characteristics  of  the  different  classes  of 
rock.  In  other  words,  the  personal  element  enters  largely  into  the 
process,  and,  as  the  quality  of  the  cement  depends  in  a  great  degree 


THE   LAWRENCE   CEMENT   COMPANY,    ROSENDALE,   N.   Y. 


AMERICAN    CEMENTS.  247 

upon  the  care  taken  in  the  calcination,  it  is  important  that  only  men 
of  experience  and  skill  should  be  employed  as  burners.  The  kilns 
are  built  of  stone  and  lined  with  brick.  In  these  kilns  a  fire  is  built, 
the  calcination  being  carried  on  by  placing  on  the  wood  used  for 
lighting  a  thin  layer  of  coal,  over  which  a  layer  of  stone  from  6  to  8 
ins.  thick  is  placed,  then  a  thin  layer  of  coal,  repeating  the  process 
as  often  as  the  removal  of  the  calcined  rock  at  the  bottom  requires 
it.  The  coal  used  is  anthracite,  usually  of  pea  or  buckwheat  size, 
and  is  placed  on  the  rock  in  very  thin  layers,  scarcely  covering  it. 
Each  morning  the  previous  day's  burning  is  removed  from  the  bot- 
tom of  the  kilns,  as  by  this  time  the  rock  has  become  sufficiently 
cool  to  be  handled.  In  drawing  the  kilns  it  is  always  found  that 
some  of  the  rock  has  been  much  overburned,  in  fact,  having 
reached  a  stage  of  incipient  vitrification,  while  another  portion,  con- 
sisting usually  of  the  larger  fragments,  is  underburned  and  perhaps 
partially  raw  inside.  The  overburned  stone  is,  of  course,  quite 
worthless,  and  is  carted  away  to  the  dumps,  but  the  underburned 
stone  is  conveyed  to  the  tops  of  the  kilns,  and  again  subjected  to  cal- 
cination. 

From  the  bottoms  of  the  kilns  the  stone,  which  has  been 
properly  calcined,  is  taken  directly  to 'the  cracker  room.  In  the 
view,  showing  the  draw  pits  of  the  kilns  at  Binnewater,  this  cracker 
room  is  just  across  the  tramway  tracks,  and  is  partly  shown  at 
the  right  hand.  In  the  cracker  room  the  rock  is  crushed  to  a 
fineness  varying  from  dust  to  lumps  of  the  size  of  a  hickory  nut,  by 
what  are  known  as  crackers.  These  are  made  of  cast  iron,  and  con- 
sist essentially  of  a  frustrum  of  a  solid  cone  called  the  core,  working 
concentrically  within  the  inverted  frustrum  of  a  hollow  cone,  both 
being  provided  on  their  adjacent  surfaces  with  suitable  grooves  and 
flanges  for  breaking  the  stone  as  it  passes  down  between  them.  The 
elements  of  the  lower  portions  of  both  cones  make  a  smaller  angle 
with  the  common  axis  than  those  pertaining  to  the  upper  portions, 
with  a  view  to  lessen  the  strain  and  the  effects  of  sudden  shocks 
upon  the  machinery,  by  securing  a  more  gradual  reduction  of  the 
stone  to  the  required  size.  These  lower  portions,  being  subject  to 
very  rapid  wearing,  are  made  of  chilled  iron,  and  are,  moreover,  cast 
in  separate  pieces  in  order  that  they  may  be  replaced  by  new  ones, 
as  the  occasion  requires.  At  the  Binnewater  mill  there  are  eight  of 


248  AMERICAN    CEMENTS. 

these  crackers  driven  by  steam  power,  which,  it  may  be  stated  here, 
is  used  in  all  of  the  company's  mills,  both  for  driving  the  mill 
machinery  proper,  and  for  running  the  various  hoisting  engines. 

After  leaving  the  crackers  all  the  cracked  cement  or  burned 
stone  goes  to  an  elevator  boot  which  is  located  two  stories,  or  about 
22  or  23  ft.  below  the  crackers,  from  which  place  it  is  elevated  by  the 
elevator  referred  to  about  33  ft.  perpendicularly,  and  there  it  is  thrown 
into  a  conveyor.  This  conveyor  carries  it  along  for  distribution  to 
the  different  mills  or  grinders,  there  being  spouts  opposite  each  mill 
leading  from  the  conveyor  to  them,  and  as  the  cracked  stone  passes 
through  the  different  spouts  it  runs  over  a  sieve  or  screen  made  of 
steel  wire  cloth.  This  sieve  is  about  1 1  ft.  long  by  10  ins.  in  width, 
and  is  fastened  into  a  box  or  portion  of  the  spout  referred  to  above, 
which  is  about  12  ins.  wide  and  6  ins.  deep,  so  that  25  to  27%  of  the 
cracked  cement  passes  through  this  sieve,  which  would  give  an  aver- 
age fineness  of  96  to  97%  when  tested  through  a  sieve  of  2,500  meshes 
to  the  square  inch. 

After  being  crushed  in  the  crackers  all  of  the  cracked  cement 
which  fails  to  pass  through  the  sieve  is  conveyed  by  chutes  directly 
to  the  grinders,  which  look  as  nearly  as  possible  like  the  stones  of  an 
ordinary  grist  mill,  as  will  be  seen  from  the  illustration  of  the  grind- 
ing room.  In  fact,  the  grinding  of  cement  is  exactly  like  the  grind- 
ing of  corn.  The  Shawangunk  conglomerate,  or  grit,  which  is 
found  in  large  quantities  in  Ulster  County,  is  used  for  the  millstones. 
At  Binnewater  there  are  16  grinders,  or,  in  other  words,  16  pairs  of 
millstones,  and  they  grind  sufficient  rock  to  make  2,500  barrels  per  day. 
The  grinders  are  placed  in  a  single  row,  and  discharge  into  boxes 
containing  screw  conveyors  which  run  from  each  end  to  the  center. 
The  ground  cement  is  thus  conveyed  from  each  grinder  to  a  central 
reservoir,  from  which  it  is  taken  by  a  bucket  conveyor  to  the  mixers. 
By  means  of  the  mixers  the  cement  coming  from  the  separate 
grinders  is  thoroughly  mixed,  and  uniformity  of  quality  secured.  To 
remove  the  cement  dust,  which  rises  thickly  from  the  grinders  and 
is  both  disagreeable  and  unwholesome  for  the  workmen,  a  powerful 
ventilating  fan  is  used.  This  fan  draws  the  dust  through  the  pipes 
shown  with  funnel-shaped  openings  for  each  grinder  in  view  of  the 
grinding  room  and  conveys  it  to  the  floor  above,  where  it  is  sepa- 
rated from  the  atmosphere  and  deposited  to  be  put  in  barrels  and 


THE   LAWRENCE   CEMENT    COMPANY,    ROSENDALE,    X.    Y. 


AMERICAN    CEMENTS.  251 

sold.     About  one  and  one  half  barrels  of  this  cement  dust  are  col- 
lected every  day  at  the  Binnewater  mill. 

From  the  mixers  the  cement  passes  by  chutes  to  the  barrels  in 
the  packing  room  (see  illustration).  The  metal  pipes  in  the  right  fore- 
ground connect  directly  with  the  mixer,  and,  as  will  be  seen,  discharge 
into  the  barrels  underneath.  To  settle  the  cement  thoroughly  in  the 
barrels,  each  is  placed  on  a  circular  iron  disk  or  table  which  is  capa- 
ble of  a  vertical  movement.  This  disk  is  connected  with  suitable 
machinery  which  lifts  it  vertically  a  few  inches,  then  suddenly 
releases  it,  allowing  it  to  fall  with  a  concussion  which  settles  the 
cement  in  the  barrel.  As  each  barrel  is  filled  it  is  removed  to  the 
scales,  where  a  man  removes  or  adds  sufficient  cement  to  bring 
the  weight  exactly  to  300  Ibs.  The  barrels  then  pass  to  men  who  put 
in  the  heads  and  label  and  stamp  them  ready  for  storage  or  shipment. 

As  stated  before,  steam  power  is  used  for  operating  the  mills. 
At  Binnewater  five  boilers  supply  steam  to  a  pair  of  Corliss  com- 
pound engines,  with  the  high  pressure  and  low  pressure  cylinders 
mounted  tandem,  driving  a  single  shaft.  The  cylinders  are  24  by 
48  ins.,  and  44  by  48  ins.  At  the  Eddyville  works  the  Wm.  Wright 
engines  are  used.  In  order  to  bring  the  equipment  of  the  two  mills 
into  convenient  position  for  comparison,  the  principal  details  are 
given  in  the  following  tables :  — 

Binnewater.  Eddyville. 

No.  of  kilns 30  36 

No.  of  crackers        8  8 

No.  of  grinders 16  16 

No.  of  packers 12  20 

Daily  capacity 2,500  barrels.       2,800  barrels. 

Storage  capacity 15,000  barrels.    25,000  barrels. 

Hickory  Bush  warehouses  storage  capacity  60,000  barrels. 

In  addition  there  are  at  the  Esopus  mills  two  crackers,  four 
grinders,  and  four  packers  with  a  daily  capacity  of  from  600  to  800 
barrels.  The  production  of  the  three  mills  in  operation  in  1896  was 
1,120,769  barrels  of  cement. 

As  an  indication  of  the  conscientious  care  displayed  by  the  com- 
pany in  the  manufacture  of  its  cement  may  be  mentioned  the  thorough 
system  of  tests  carried  out.  The  daily  product  is  subjected  to  an 
examination  as  regards  fineness,  setting  qualities,  and  strength.  Not 


252  AMERICAN    CEMENTS. 

only  is  this  done  every  half  hour  of  the  day  before  the  cement  leaves 
the  mills,  but  in  the  New  York  office  laboratory  tests  are  made  of 
each  day's  grinding. 

In  this  brief  statement  of  the  manufacture  of  cement  by  the 
Lawrence  Cement  Company,  it  will  be  noticed  that  the  manufacture 
of  supplies  for  the  mills  forms  industries  of  very  respectable  magni- 
tude in  themselves.  The  most  noteworthy  of  these  is  the  manufac- 
ture of  the  barrels  in  which  the  cement  is  packed.  This  is  all  done 
by  the  company,  cooper  shops  being  located  at  each  of  the  mills. 
At  these  shops  are  facilities  for  manufacturing  the  barrels  complete, 
lining  them  with  paper  and  storing  them  for  use.  The  raw  materials, 
hoops,  staves,  heads,  etc.,  are  stored  in  and  about  the  mills.  At 
Eddyville  the  company  has  a  large  boat  yard,  where  repairs  are 
made  to  its  fleet  of  boats,  about  fifteen  of  which  are  used  to  trans- 
port the  cement  on  the  canal  and  down  the  Hudson  River.  In 
addition,  at  each  mill  blacksmith  and  carpenter  shops  are  located, 
where  repairs  are  made  to  the  drills,  tram  cars,  and  tools  used  in  the 
quarries  and  about  the  mills. 

A  very  prominent  factor  in  an  industry  requiring  frequent  ship- 
ments of  cargoes  of  large  bulk  and  weight  is,  of  course,  the  proxim- 
ity of  transportation  lines  in  the  center  of  production.  It  is  a 
somewhat  curious,  and,  withal,  very  important  fact  that  nearly  all  of 
the  present  cement  rock  quarries  were  discovered  while  constructing 
the  great  waterways  in  the  early  part  of  the  century,  and  the  first  use 
of  the  cement  manufactured  was  in  the  masonry  of  the  locks,  walls, 
and  bridges  of  these  canals.  The  constructions  of  the  Delaware 
and  Hudson  Canal  first  disclosed  the  cement  rock  of  Ulster  County } 
and,  until  recently,  furnished  the  means  of  transportation  for  the 
greater  part  of  the  cement  manufactured  by  the  Lawrence  Cement 
Company  from  the  quarries  brought  to  light  in  its  construction.  The 
company  has  two  shipping  points,  viz.,  at  Binnewater  and  Eddyville. 
At  Binnewater  the  works  are  located  within  a  few  rods  of  the  Wall- 
kill  Valley  Railroad,  and  all  of  the  cement  manufactured  here  is 
shipped  by  railway.  The  works  at  Eddyville  are  located  on  Rond- 
out  Creek,  and  here  are  built  extensive  docks  for  the  boats  used  in 
the  transportation  of  cement  to  all  points  reached  by  the  canal  and 
river.  The  production  of  the  Eddyville  mill,  2,800  barrels  daily,  is 
shipped  at  this  point. 


AMERICAN    CEMENTS.  253 

The  Lawrence  Cement  Company,  like  many  other  large  com- 
panies, has  undergone  many  changes  in  its  organization  and  person- 
nel. Taking  its  name  originally  from  Mr.  W.  E.  Lawrence,  who 
made  the  first  cement  in  1832,  the  company  in  1853  reorganized 
under  its  present  title.  At  the  same  time  the  works  were  enlarged 
and  the  name  of  the  brand  of  cement  changed  to  "  Hoffman"  Ros- 
endale  Cement,  of  which  more  than  twelve  millions  of  barrels  have 
been  manufactured  since  and  used  in  the  construction  of  important 
buildings  and  municipal,  railroad,  and  government  work. 

DESCRIPTION    OF    THE    WORKS    OF    THE    EMPIRE 
PORTLAND  CEMENT  COMPANY,  WARNERS,  N.  Y. 

MARL  AND  CLAY  DEPOSIT. —  The  marl  consists  of  carbonate 
of  lime,  varying  in  depth  from  3  to  1 8  ft.  The  blue  clay  is  imme- 
diately under  the  marl.  Following  is  the  analysis  of  the  marl  and 
clay :  — 

BLUE    CLAY.  MARL. 

Silica 40.48  Silica .26 

Alumina  and  iron  oxide  .  20.95  Alumina  and  iron  oxide  .  .10 

Carbonate  of  lime  .     .     .  25.80  Carbonate  of  lime  .     .     .  94.39 

Magnesia 99  Magnesia 38 

Potash 3.14  Organic  matter  .     ...  1.54 

Water  and  organic  mat-  Water 3.10 

ter 8.50 

99.86  99.77 

There  is  from  6  to  1 2  ins.  of  muck  overlying  the  marl  deposit. 
The  marl  and  clay  is  excavated  with  a  revolving  derrick,  with  clam- 
shell digger,  which  lifts  a  yard  and  one  half  each  dip ;  the  marl  and 
clay  is  loaded  separately  on  cars  having  a  capacity  of  3  yds.  each. 
The  cars  of  marl  and  clay  are  delivered  to  the  works,  which  are  one 
mile  distant,  by  means  of  a  narrow  gauge  railroad. 

MIXING  DEPARTMENT. —  The  cars  of  marl  and  clay  are  hauled 
up  an  inclined  track,  by  means  of  steel  cable  and  hoisting  drum,  onto 
the  second  floor  of  the  mixing  department.  The  clay  is  delivered  to 
two  large  rotary  drying  cylinders,  where  the  moisture  is  driven  off; 
the  dried  clay  then  passes  through  steel  elevators  and  conveyors,  the 
heat  being  carried  off  with  suction  fans  as  the  material  passes 
through  the  conveyors ;  it  is  then  delivered  into  large  steel  bins,  and 


254  AMERICAN    CEMENTS. 

from  there  passes  into  under-runner  emery  mill  stones,  where  it  is 
ground  to  an  impalpable  powder ;  it  is  then  delivered  into  large  steel 
storage  bins  over  the  mixing  pans. 

The  marl  is  delivered  direct  from  the  cars  to  the  mixing  pans; 
the  dry  ground  clay  is  drawn  from  the  storage  bin  and  delivered 
into  scale  hopper,  where  the  proper  proportion  is  weighed  and  dis- 
charged into  the  mixing  pan  on  top  of  the  marl ;  this  constitutes  one 
charge  of  3  cu.  yds.  of  marl  with  proper  amount  of  clay.  The 
material  is  thoroughly  mixed,  sample  of  the  mixed  material  is  taken 
to  the  laboratory,  where  proper  tests  are  made,  to  determine  if  the 
mixture  is  correct ;  this  being  done,  the  material  is  discharged  into 
brick  machines,  and  from  there  delivered  onto  iron  or  wood  pallets 
which  are  5  ins.  wide  by  48  ins.  long;  52  of  these  loaded  pallets  are 
placed  on  each  iron  car. 

The  cars  of  brick  are  passed  into  hot-air  drying  tunnels,  where 
the  moisture  is  entirely  driven  oft.  The  brick  carry  about  35  per 
cent,  of  moisture  as  they  go  to  the  drying  tunnels.  The  drying  tun- 
nels are  100  ft.  long,  4  ft.  4  ins.  wide,  and  5  ft.  6  ins.  high  ;  each  tunnel 
will  accommodate  1 7  of  the  cars  of  brick,  there  are  in  all  29  tunnels. 
It  requires  from  30  to  36  hours  to  thoroughly  dry  the  brick. 

The  burning  kilns  are  the  ordinary  type  of  dome  kilns,  with 
added  improvements  to  facilitate  the  rilling  and  for  the  utilization  of 
the  waste  heat.  20  of  these  kilns  are  used,  10  on  each  side. 

The  dry  brick  are  elevated  with  power  elevator  to  the  different 
floors  of  the  burning  kilns.  The  kilns  are  filled  with  alternate  layers 
of  the  dry  brick  and  coke.  About  60  cars  of  the  dry  brick  are  put 
in  each  kiln  with  about  4^  tons  of  coke.  After  the  kiln  is  filled 
with  the  alternate  layers  of  coke  and  dry  brick,  the  doors  are  sealed 
and  the  fire  is  started  below.  The  temperature  gradually  rises  to  a 
white  heat  and  slowly  rises  to  the  top  ;  while  the  kiln  is  burning  no 
attention  is  necessary.  When  the  fire  has  reached  the  top  the  stack 
of  the  kiln  is  covered  and  the  heat  is  drawn  off  by  a  system  of  suc- 
tion fans,  and  utilized  for  drying  the  wet  brick.  As  soon  as  the 
clinker  is  sufficiently  cool  it  is  removed  from  the  lower  part  of  the 
kiln,  where  it  is  carefully  selected  and  delivered  to  the  crushing 
machinery. 

The  time  required  for  charging,  burning,  and  emptying  a  kiln  is 
from  5  to  6  days.  Each  kiln  produces  from  20  to  22  tons  of  clinker. 


EMPIRE   PORTLAND   CEMENT    COMPANY,   WARNERS,   N.   Y. 


**         OFTHB    ^F 

UNIVERSITY 


AMERICAN    CEMENTS.  263 

The  clinker  passes  through  crushers  and  rolls  until  it  is  reduced 
fine  enough  so  that  the  coarsest  particles  will  pass  a  No.  8  sieve  I 
it  is  then  delivered  to  emery  millstones,  where  it  is  finely  ground. 

From  the  millstones  it  passes  through  a  vacuum  separator,  the 
coarse  particles  being  returned  for  further  reduction.  The  finished 
product  is  so  finely  ground  that  95  per  cent,  will  pass  a  10,000  mesh 
sieve. 

The  finished  product  is  conveyed  to  the  storehouse,  which  is 
arranged  with  a  system  of  bins  having  a  capacity  of  25,000  barrels. 

From  the  storage  bins  the  cement  is  conveyed  to  a  barrel 
packer,  which  is  adapted  for  filling  in  either  barrels  or  sacks. 

One  barrel  of  the  Portland  cement  weighs  400  Ibs.  gross,  380 
Ibs.  net. 

The  laboratory  and  testing  department  is  under  the  super- 
vision of  experts,  and  is  equipped  with  the  most  modern  chemical 
and  mechanical  appliances. 

By  continuous  chemical  analyses  of  the  marl  and  clay  the  com- 
position of  the  mixture  is  kept  absolutely  correct,  thus  insuring  a 
uniform  quality.  In  addition  to  this,  frequent  analyses  are  made  of 
the  finished  product.  The  cement  manufactured  each  day  is  tested 
to  determine  the  tensile  strength,  both  neat  and  with  sand,  for 
periods  ranging  from  48  hours  to  1 2  months :  tensile  test  for  48  hours 
and  7  days  is  also  made  of  each  shipment,  so  at  any  time  tests 
can  be  furnished  on  any  particular  lot.  These  tests,  together  with 
important  engineering  works  which  have  been  constructed  with  Em- 
pire Portland  cement,  demonstrate  beyond  a  doubt  that  it  has  no 
superior. 

The  high  standard  attained  by  the  Empire  Portland  cement  has 
only  been  secured  by  the  expenditure  of  over  half  a  million  dollars, 
and  the  devising  of  improved  machinery,  in  the  erection  of  large  and 
commodious  buildings,  and  the  employment  of  skilled  help  in  the 
manufacturing  departments. 

Possessing  a  practically  inexhaustible  supply  of  the  very  best  of 
raw  material,  and  aided  by  the  employment  of  all  the  appliances  that 
money  can  command,  it  is  the  steadfast  purpose  of  the  Empire  Port- 
land Cement  Company  to  produce  a  Portland  cement  which  shall 
be  to-day,  to-morrow,  and  for  the  years  to  come,  always  the  same, 
always  reliable. 


2(34  AMERICAN    CEMENTS. 


CHAPTER  IX. 

THE  USES  OF  CEMENT — INCREASING  USE  PER  CAPITA  —  CON- 
CRETE GROWING  IN  FAVOR  —  SAND  CEMENT  —  DISCREPAN- 
CIES IN  THE  PROPORTIONS  OF  SAND  BY  MEASURE  OR  WEIGHT 

—  TABLE  OF  WEIGHTS  AND  MEASURES — VOLUME  vs.  WEIGHT 

—  ULTIMATE  STRENGTH  OF  BOTH    CLASSES  OF  CEMENTS  — 
MACHINE  vs.  HAND-MADE   MORTAR   AND   CONCRETE  —  DIS- 
ASTROUS RESULTS  FROM.  POORLY  MADE  CEMENT  MORTAR  — 
ANCIENT  MORTAR  SCIENTIFICALLY  MADE  —  THE  AUTHOR'S 
COLLECTION  OF  ANCIENT  MORTARS  AND  CONCRETES — THE 
FORMATION    OF    STONE    BY    NATURAL    INFILTRATION  —  BY 
ARTIFICIAL    INFILTRATION  AS    PRACTISED   BY  THE   MOUND- 
BUILDERS —  THE    NATURAL    PROCESS    IN    THE    FORMATION 
OF  HYDRAULIC  CEMENT  ROCKS  —  STATISTICS  OF  THE  ROCK 
CEMENT  INDUSTRY  IN  THE  UNITED  STATES — IMPORTS  AND 
DOMESTIC    PORTLAND    TABLE    OF    STATISTICS  —  NOTABLE 
STRUCTURES    LAID     IN    ROCK    CEMENT  —  A    WONDERFUL 
RECORD. 

The  use  of  cement  is  largely  on  the  increase  in  this  country,  as 
may  be  seen  by  the  following  table  showing  the  number  of  pounds 
of  Rock  cement  consumed  per  capita  at  the  dates  given :  — • 

1850     pounds  per  capita 646 

1860  „         „         „          .........  10.49 

1870  „         „         „          .........  12.77 

1880  „         „         „          .........  13.04 

1890  „         „         ..........  33.93 

The  older  States  consume  more  cement  per  capita  than  do  the 
younger  States. 


AMERICAN   CEMENTS.  265 

In  the  larger  cities  the  brick  and  stone  buildings  are  being  laid 
in  cement,  whereas  in  former  years  quicklime  was  used  for  the 
purpose. 

The  use  of  concrete  is  rapidly  increasing.  It  is  being  adopted 
in  places  where  not  many  years  ago  it  was  considered  unsafe  to  use 
anything  but  heavy  stone  masonry. 

The  new  $4,000,000  Federal  building  in  Chicago  will  stand  on  a 
series  of  points  instead  of  resting  on  a  foundation  extending  evenly 
along  the  entire  wall  line.  The  weight  of  the  huge  structure  will  be 
so  adjusted  that  it  will  rest  on  concrete  columns  32  ft.  apart,  these 
columns  going  down  to  bed  rock  72  ft.  below  the  surface  of  the 
earth.  This  is  the  plan  adopted  in  modern  bridge  building,  and 
represents  the  most  advanced  progress  in  that  field  of  construction. 
The  mode  of  excavating  for  the  foundation  is  very  interesting  and 
simplicity  itself.  A  section  of  a  wrought-iron  tube  of  the  desired 
diameter  is  set  upon  the  ground  on  its  rim,  and  as  the  earth  within 
the  circle  is  removed  the  tube  sinks.  When  the  top  of  the  first 
section  settles  down  to  the  level  of  the  earth's  surface  a  second  sec- 
tion is  placed  above  it  and  the  digging  process  is  continued.  One 
section  after  another  disappears,  and  bed  rock  is  eventually  reached 
without  the  slightest  disturbance  occurring  to  the  surrounding  ma- 
terial. There  is  no  settling  of  neighboring  foundations,  no  tottering 
walls,  no  alarm  or  disquiet  of  any  sort. 

When  the  excavation  is  completed  there  is  a  clean  iron-walled 
hole  into  which  the  concrete  is  poured  and  subjected  to  the  necessary 
pressure.  When  the  iron  tube  is  filled  the  job  is  finished,  the  iron 
casing  being  allowed  to  remain.  The  columns  which  will  constitute 
the  foundation  for  the  Chicago  building  will  vary  in  diameter  from 
1 2  to  1 5  ft.  Through  the  wear  and  tear  of  ages  they  will  support  all 
the  weight  that  they  will  be  called  upon  to  bear. 

By  this  plan  it  will  not  be  necessary  to  drive  piling  down  to 
bed  rock  or  to  resort  to  any  of  the  methods  for  making  broad  bases 
for  foundations  to  rest  upon,  so  familiar  to  Chicago  builders  of  lofty 
edifices  and  heavy  business  blocks.  The  element  of  uncertainty  will 
be  entirely  eliminated.  Concrete  columns  have  been  tried  in  the 
construction  of  all  the  great  iron  and  steel  bridges  built  in  recent 
years  and  found  to  be  wholly  satisfactory.  There  is  no  guesswork, 
no  speculation  as  to  the  precise  weight  a  concrete  column  of  certain 


266  AMERICAN    CEMENTS. 

dimensions  standing  on  solid  rock  will  sustain.  It  is  a  simple  mathe- 
matical and  engineering  proposition. 

The  concrete  will  be  composed  of  American  Portland  cement 
one  part,  sand  two  parts,  and  five  parts  of  broken  stone. 

The  foregoing  description  is  derived  from  Chicago  journals  and 
private  correspondence. 

For  concrete  sidewalks  for  the  Federal  building  at  Mankato, 
Minn.,  in  1896,  the  following  specifications  were  drawn  by  William 
M.  Aikin,  United  States  Supervising  Architect,  Washington,  D.  C. :  — 

"  The  bed  for  sidewalk  to  be  excavated  to  the  required  depth, 
and  the  sidewalk  constructed  as  follows  "  :  — 

"  A  6  in.  thick  layer  of  broken  stone,  same  as  hereinafter 
specified  for  concrete,  thoroughly  rolled  solid  ;  on  this  lay  a  6  in. 
thick  layer  of  concrete  and  a  2  in.  thick  finish  coat.  The  concrete 
to  be  composed  of  five  parts  sound  hard  stone,  broken  to  a  size  to 
pass  through  a  2  in.  diameter  ring  ;  two  parts  clean,  sharp  sand,  and 
one  part  of  approved  hydraulic  cement.  Sand  and  cement  to  be 
mixed  dry.  Water  added  to  make  a  mortar  of  proper  consistency, 
and  the  broken  stone,  drenched  and  drained,  to  be  stirred  in  until 
each  piece  is  thoroughly  coated. 

"  The  concrete  to  be  laid  and  tamped  until  free  mortar  appears 
on  the  surface. 

"  The  concrete  to  be  laid  in  blocks,  and  as  near  4  ft.  square  as 
may  conform  to  width  of  sidewalk. 

"  These  blocks  to  be  cut  clear  through,  down  to  broken  stone  base. 

"  The  finish  coat  to  be  composed  of  two  parts  approved  Portland 
cement,  and  three  parts  of  clean  crushed  granite,  all  thoroughly 
mixed,  tempered,  laid  in  place  and  properly  tamped  with  wooden 
tamps,  and  have  a  dry  coat  of  two  parts  cement  and  one  part  sharp 
white  sand  floated  on,  troweled  down  to  a  smooth,  hard  finish,  and 
the  surface  slightly  indented  for  foothold. 

"  The  finish  coat  to  be  cut  through  on  lines  corresponding  with 
the  concrete  blocks  below.  The  finish  surface  of  the  sidewalk  to  be 
graded  as  shown  and  noted  on  the  drawing. 

QUALITY    OF    CEMENT. 

"  The  Portland  cement,  herein  called  for,  to  have  a  tensile 
strength  of  not  less  than  350  Ibs.  to  square  inch. 


AMERICAN    CEMENTS.  267 

"  That  for  hydraulic  cement  to  be  90  Ibs. 

"  Samples  of  the  cement,  proposed  to  be  used  for  the  work,  must 
be  submitted  by  the  contractor  for  test,  about  2  qts.  of  each  kind. 
(It  is  presumed  that  7  day  tests  are  meant.  —  AUTHOR.) 

•«  Samples  of  the  cement  delivered  on  the  premises  for  use  in 
actual  construction  will  be  subject  to  test ;  and  all  cement  found  to 
be  unsatisfactory  will  be  rejected,  and  the  same  must  be  immediately 
removed  from  the  premises. 

"  The  names  and  brands  of  cements  proposed  to  be  used  must 
be  stated  in  the  bid ;  and  all  cements  must  be  of  uniform  quality; 
not  damaged  ;  satisfactory  to  the  supervising  architect ;  delivered  on 
the  site,  in  the  original  packages,  with  the  brand  and  makers'  name 
plainly  printed  or  stenciled  thereon,  and  kept  dry  until  used." 

A.  S.  Cooper,  in  Journal  Franklin  Institute,  November,  1895, 
writes  as  follows  in  regard  to  fine  vs.  coarse  sand  for  a  cement 
mortar :  — 

"  During  the  construction  of  a  mining  casemate  at  Fort  Pulaski  last 
year  the  question  arose  as  to  the  advisability  of  using  fine  beach  sand  in- 
stead of  coarse  river  sand,  on  account  of  the  greater  cost  of  obtaining  the 
latter.  The  writer  took  the  position  that  fine  sand  would  be  nearly  as 
good,  and  as  it  was  estimated  to  save  nearly  $1,000  in  the  total  cost,  ex- 
periments were  made  which  proved  the  fine  sand  to  be  slightly  stronger 
than  the  coarse.  These  results  are  opposed  to  those  obtained  by  all 
previous  experimenters.  Generally  speaking,  the  coarser  the  sand  the 
stronger  the  mortar  made  from  it ;  but  the  difference  between  the  grades 
below  30-40  are  so  slight  that,  as  far  as  sizes  are  concerned,  they  might  be 
considered  in  one  class.  There  seemed  to  be  a  tendency  toward  an  in- 
crease in  strength  with  grades  below  100-120,  but  so  few  samples  of  these 
grades  were  obtained  that  this  slight  increase  may  be  put  down  as  acciden- 
tal. There  is  an  unmistakable  indication  of  weakness  in  the  upper  grade, 
8-12.  It  is  apparent  that  the  specific  gravity  of  all  of  the  various  kinds 
and  grades  of  sand  tried  are  not  materially  different,  and  that  therefore  the 
difference  found  between  the  weights  of  different  volumes  are  principally 
due  to  the  different  percentages  of  voids.  It  is  further  apparent  that  the 
smaller  the  grade,  the  greater  percentage  of  voids  in  loose  sand,  and  vice 
versa  ;  while  in  well-packed  sand  there  is  practically  no  difference  in  per- 
centage of  voids.  These  results  indicate  that  uniformity  of  mortar 
briquettes  for  tests  can  be  obtained  only  by  either  measuring  the  sand 
while  well  packed  or  by  weighing.  Other  things  being  equal,  coarse  sands 


268  AMERICAN    CEMENTS. 

are  better  than  fine  sands  for  cement  mortar  up  to  the  grade  12-16,  or 
about  one  twelfth  of  an  inch  in  diameter.  Below  the  grade  40-50,  or 
about  one  sixtieth  erf  an  inch  in  diameter,  there  is  no  practical  difference 
in  the  value  of  the  different  sands,  as  far  as  the  size  is  concerned.  The 
shape  and  condition  of  the  surfaces  of  the  grains  of  different  sands  has  as 
much  to  do  with  the  value  of  cement  mortar  as  the  size." 


In  the  selection  of  sand  for  cement  mortar  or  concrete  it  is  im- 
portant to  know  that  the  amount  which  may  safely  be  used  depends 
largely  on  its  purity. 

It  is  by  no  means  an  easy  matter  to  find  pure  sand.  A  portion 
of  a  handful  dropped  into  a  glass  of  clear  water  will  demonstrate 
quite  accurately  its  condition. 

If  absolutely  pure,  the  sand  will  settle,  leaving  the  water  clear. 

If  it  contains  clay  or  loam,  those  impurities  will  cloud  or  discolor 
the  water. 

The  impurities  named  are  by  no  means  fatal  to  a  mortar  or  con- 
crete, but  the  sand  containing  them  cannot  be  used  as  freely  as  one 
that  is  pure. 

Either  one  of  the  impurities  named,  if  present,  will  retard  the 
setting  of  the  cement,  the  degree  of  retardation  being  in  direct  ratio 
with  the  percentage  of  impurities  present. 

It  is  understood  that  ordinary  clean  sand  contains  voids  amount- 
ing usually  to  about  one  third  of  the  total  volume.  It  will  be  seen, 
then,  that  with  three  barrels  of  sand  the  voids  may  be  replaced  by  a 
barrel  of  cement  without  an  increase  in  volume. 

It  will  also  be  apparent  that,  if  more  than  three  parts  of  sand 
to  one  of  cement  are  used,  whether  the  latter  is  Rock  cement  or 
Portland,  there  will  be  voids  amounting  to  one  third  of  the  volume 
of  sand  used  in  excess. 

If  one  barrel  of  cement  and  three  barrels  of  sand  are  mixed 
together,  and  the  latter  contains  loam  or  clay,  the  voids,  instead  of 
being  filled  with  pure  cement,  will  be  filled  with  cement  which,  by 
reason  of  its  being  mixed  with  the  impurities  named,  will  be  greatly 
retarded  in  setting. 

Within  the  past  few  years  there  has  been  placed  upon  the 
market  a  cement  known  as  "sand"  cement.  It  is  produced  by 
grinding  together  to  a  fine  condition  a  mixture  of  Portland  cement 


AMERICAN    CEMENTS.  269 

and  sand,  usually  in  the  proportions  of  one  barrel  of  cement  and 
three  barrels  of  sand. 

It  is  claimed  by  the  advocates  of  this  kind  of  cement  that  it 
will  test  equally  as  high,  when  mixed  with  three  parts  of  sand,  as  will 
the  pure  Portland  when  mixed  with  the  same  amount. 

In  other  words,  by  reason  of  the  fine  trituration  of  the  cement 
and  three  parts  of  sand,  the  original  one  part  of  cement  will  carry 
six  parts  of  sand,  and  test  equally  as  high  as  the  one  part  of  cement 
and  three  parts  of  sand  mixed  in  the  ordinary  manner. 

However  true  it  may  be  in  regard  to  the  tests  being  equal,  it 
can  readily  be  seen,  if  three  parts  of  ordinary  sand  are  mixed  with 
one  part  of  the  "  sand  "  cement,  that  the  voids  are  filled  with  a  mortar 
instead  of  being  filled  with  pure  cement. 

And  as  but  one  fourth  of  this  mortar  is  cement,  and  as  it  is  a 
fact  that  it  is  only  the  cement  in  the  mortar  which  has  any  setting 
properties  whatever,  it  would  seem,  if  there  is  any  benefit  to  be 
derived  from  the  use  of  the  so-called  "  sand  "  cement,  it  must  follow 
that  a  cement  mortar  can  be  made  to  equal  the  pure  cement  in 
strength,  a  proposition  which  on  its  face  appears  to  be  unsound,  not- 
withstanding the  results  as  claimed  to  be  shown  by  the  testing  machine. 

The  report  of  the  committee  on  a  "  Uniform  System  for  Tests  of 
Cement,"  to  the  American  Society  of  Civil  Engineers,  states  that 
"  the  proportions  of  cement,  sand,  and  water  should  be  carefully 
determined  by  weight." 

This  practise  of  determining  proportions  by  weight  in  the  mak- 
ing of  briquettes  for  testing  purposes  is  quite  rigidly  adhered  to,  but 
whenever  cement  mortar  is  made  for  masonry  work  there  is  a  wide 
departure  from  the  rules  observed  in  testing. 

In  the  mixing  of  cement  mortar,  it  is  customary  throughout  the 
country  to  use  an  empty  cement  barrel  for  measuring  the  sand  that 
is  to  be  mixed  with  the  cement. 

There  are,  in  this  country,  three  distinct  standards  of  weight 
for  a  barrel  of  cement. 

The  standard  weight  throughout  the  Eastern  and  Atlantic  States 
is  known  as  the  "  Eastern "  weight  for  Rock  cement,  while  the 
"Western"  weight  is  prevalent  through  the  Middle  and  Western 
States. 

The  Portland  weight  is  the  same  throughout  the  country. 


270  AMERICAN    CEMENTS. 

TABLE   OF    STANDARD    WEIGHTS    PER    BARREL. 

Net  weight  of  a  barrel  of  Eastern  cement  is  300  Ibs. 
Net  weight  of  a  barrel  of  Western  cement  is  265  Ibs. 
Net  weight  of  a  barrel  of  Portland  cement  is  380  Ibs. 
Net  weight  of  a  barrel  of  sand  is  300  Ibs. 

It  is  customary  in  the  use  of  Rock  cements  to  spread  out  two 
barrels  of  sand  in  a  mortar  box,  and  over  this  spread  one  barrel  of 
cement,  and  these  are  mixed  together  while  dry,  and  water  is  then 
applied. 

If  Portland  cement  is  to  be  used,  it  is  customary  to  employ  three 
barrels  of  sand  to  one  barrel  of  cement. 

This  manner  of  measuring  is  practised  throughout  the  entire 
country,  and  while  it  is  a  convenient  system,  it  results  in  a  disparity 
of  proportions  when  weights  are  considered,  which  militates  against 
the  Rock  cements,  and  correspondingly  favors  the  Portland  cements. 

It  also  favors  the  Eastern  as  against  the  Western  cements,  as 
will  be  seen  by  the  following :  — 


TABLE : — 

RATIOS  OF  CEMENT  AND  SAND  BY  WEIGHT  AND  MEASURE,  AND 
PER  CENT.  BY  WEIGHT. 


PORTLAND 
CEMENT. 

Ratio  by  measure. 

Ratio  by 
weight. 

Per  cent,  by 
weight. 

Cement     i 
Sand         i 

1.  00 

•79 

56 

44 

Cement     i 
Sand         2 

I.OO 

1.58 

39 
61 

Cement     i 
Sand         3 

I.OO 

2.37 

3° 
70 

Cement     i 
Sand         4 

I.OO 

3.36 

24 
76 

Cement     i 
Sand         5 

I.OO 

3.95 

20 
80 

Cement     i 
Sand         6 

I.OO 

4-74 

17 
83 

AMERICAN    CEMENTS. 


271 


Ratio  by  measure. 

Ratio  by 
weight. 

Per  cent,  by 
weight. 

"EASTERN"  ROCK 
CEMENT. 

Cement     i 
Sand         i 

1.  00 
I.OO 

5° 
50 

Cement     i 
Sand         2 

I.OO 
2.00 

33 
67 

Cement     i 
Sand         3 

I.OO 
3.00 

25 
75 

Cement     i 
Sand         4 

I.OO 
4.00 

20 
80 

Cement     i 
Sand         5 

I.OO 
5.OO 

17 
83 

Cement     i 
Sand         6 

I.OO 

6.00 

14 

86 

"WESTERN"  ROCK 
CEMENT. 

Cement     i 
Sand         i 

I.OO 

1.13 

47 
53 

Cement     i 
Sand         2 

I.OO 

2.26 

3i 
69 

Cement     i 
Sand         3 

I.OO 

3.39 

23 

77 

Cement     i 
Sand         4 

I.OO 

4-53 

18 
82 

Cement     i 
Sand         5 

I.OO 

5.66 

15 

85 

Cement     i 
Sand         6 

I.OO 

6.79 

13 

87 

It  will  be  seen  in  all  the  mixtures  of  cement  and  sand  by  meas- 
ure throughout  the  entire  table,  that  by  weight,  the  Eastern  Rock 
cement  is  carrying  26  per  cent.,  and  the  Western  43  per  cent,  more 
sand  than  is  the  Portland. 

It  will  also  be  seen  that  with  Rock  cements  at  i  to  2,  and  the 
Portland  at  i  to  3  by  measure,  the  difference  in  the  percentages  of  sand 
by  weight  is  but  a  trifle,  while  the  percentages  of  sand  in  the  Rock 
cement  at  i  to  3  and  the  Portland  at  i  to  4  are  practically  the  same. 

By  weight,  there  is  1 5  per  cent,  more  sand  in  Western  cement 
mixed  i  to  4  by  measure,  than  there  is  in  Portland  mixed  i  to  5 ; 
while  with  Eastern  cement  mixed  i  to  4,  the  percentage  of  sand  is 
precisely  the  same  as  with  Portland  mixed  I  to  5. 


272  AMERICAN   CEMENTS. 

So  long  as  it  remains  the  prevailing  custom  to  mix  cement  and 
sand  by  measure  rather  than  by  weight,  it  is  not  strange  that  people 
are  deluded  into  a  belief  that  Portland  cement  will  carry  50  per  cent, 
more  sand  than  will  the  Rock  cements. 

It  is  due  to  the  unfortunate  establishment  of  the  different 
standards  of  weight  per  barrel  that  has  led  to  many  errors  in  judg- 
ment concerning  the  relative  values  of  the  two  classes  of  cements. 

There  is  a  very  large  question  involved  in  the  matter  of  bulk  as 
between  the  two  classes  of  cements. 

The  volume  of  a  given  number  of  pounds  of  Rock  cement  is 
25  per  cent,  greater  than  is  that  of  the  same  number  of  pounds  of 
Portland  cement. 

In  the  production  of  concrete,  when  the  surfaces  of  the  sand, 
gravel,  and  broken  stone  are  fairly  coated  with  cement,  and  the  sizes 
of  the  gang  are  selected  with  a  view  to  the  prevention  of  voids,  and 
the  mass  is  properly  rammed,  it  is  generally  understood  and  admitted 
that  all  has  been  done  that  is  possible  toward  the  production  of  a 
first  quality  of  concrete. 

If,  therefore,  the  volume  of  100  Ibs.  of  Rock  cement  is  25 
per  cent,  greater  than  is  that  of  100  Ibs.  of  Portland  cement,  and 
assuming  that  both  classes  are  ground  equally  fine,  it  is  difficult  to 
disprove  that  100  Ibs.  of  Rock  cement  will  not  coat  over  the  sur- 
faces of  25  per  cent,  more  sand  and  gravel  than  the  100  Ibs.  of 
Portland. 

In  any  event,  it  must  be  clear  that,  pound  for  pound,  the  Rock 
cement  will  coat  over  an  equal  amount  of  sand  and  gravel  more 
thoroughly  than  the  Portland  cement. 

Herein  undoubtedly  is  to  be  found  the  solution  of  a  problem 
which  has  puzzled  the  cement  world  since  the  foundation  of  the  pres- 
ent system  of  cement  testing ;  namely,  that  as  the  proportion  of 
sand  is  increased,  the  difference  in  the  relative  strength  of  the  two 
classes  of  cements  decreases. 

This  fact  would  seem  to  indicate  that  the  Rock  cement,  by  hav- 
ing the  greater  volume,  has  a  greater  capacity  for  coating  over  the 
surfaces  of  the  gang  in  mortar  or  concrete. 

May  we  not  find  here  the  cause  for  the  unexpected  results  that 
were  met  with  by  Mr.  Smith  when  he  tested  the  two  classes  of 
cements  by  shearing  strain  and  by  compression  ?  He  used  twice  as 


AMERICAN    CEMENTS.  273 

much  sand  with  the  Portland  as  he  did  with  the  Rock  cement,  and 
in  the  tests  the  latter  named  cement  tested  more  than  100  per  cent, 
higher  than  the  Portland,  a  result  so  surprising  as  to  bring  out  the 
comments  by  the  author  of  the  tests,  on  pages  143,  146,  and  147, 
which  will  well  repay  careful  perusal. 

It  is  a  popular  delusion  concerning  Portland  cement,  that  there 
is  hardly  a  limit  to  its  sand-carrying  capacity,  and  oftentimes  it  is 
overloaded,  producing  a  weak,  dangerous  mortar,  which  can  in  no 
manner  compare,  either  in  cost  or  quality,  with  a  mortar  made  of 
Rock  cement  and  a  lower  admixture  of  sand. 

The  ultimate  strength  of  neat  Portland  cement  is  reached  in  one 
year,  and  one  half  of  its  strength  is  reached  in  seven  days ;  while 
with  a  mixture  of  one  part  of  cement  and  three  parts  of  sand,  it 
reaches  its  ultimate  strength  in  four  years. 

The  ultimate  strength  of  neat  Rock  cement  is  reached  in  five 
years,  and  at  seven  days  it  has  attained  but  one  eighth  of  its  ultimate 
strength  ;  while  with  one  part  of  cement  and  three  parts  of  sand  its 
ultimate  strength  is  not  known  to  the  author  beyond  ten  years,  but 
it  is  certain  that  there  is  a  gradual  increase  in  strength  during  the 
period  named. 


MACHINE  vs.  HAND  MADE  MORTARS  AND 
CONCRETES. 

One  of  the  most  approved  forms  of  concrete  mixing  machines 
is  shown  in  the  following  illustration. 

In  these  machines  the  feed  and  discharge  are  continuous,  the 
capacity  being  30  cu.  yds.  of  well-mixed  concrete  per  hour. 

They  are  largely  used  where  extensive  work  is  to  be  done,  such 
as  in  the  construction  of  reservoirs,  bridge-piers,  sea-walls,  jetties, 
and  heavy  foundations  for  business  blocks,  and  wherever  concrete 
is  to  be  used  in  large  quantities. 

It  is  claimed  that  by  the  use  of  these  machines  the  cost  of  mix- 
ing is  reduced  to  at  least  one  half  below  that  of  hand-mixed  concrete. 

It  is  beyond  question  that  machine-made  concrete  is  vastly 
superior  to  the  hand  mixed,  as  it  is  next  to  impossible  to  perform 
such  work  as  thoroughly  by  hand,  except  at  the  expense  of  much 


274 


AMERICAN    CEMENTS. 


AMERICAN    CEMENTS. 


275 


longer  time,  and  even  then  there  is  the   constant  factor  of  .human 
weakness. 

In  the  making  of  concrete  by  hand,  it  is  doubtful  if  one  set  of 
hands  can  produce  two  batches  of  equal  merit.  In  the  mixing  by 
hand  of  ordinary  cement  mortar,  where  the  specifications  call  for 
cement  one  and  sand  two  parts,  the  amount  of  mixing  the  material 
receives  depends  largely  upon  circumstances,  and  it  is  strange  that 
the  masonry  work  throughout  the  country  stands  as  well  as  it  does, 
for  on  many  works  of  importance  the  quality  of  the  mortar  as  regards 
mixing,  is  simply  wretched. 

During  the  past  summer  the  stone  piers  for  a  railroad  bridge 
over  a  small  river  near  the  home  of  the  author  were  under  construction. 

The  specifications  governing  the  quality  of  the  mortar  called 
for  a  mixture  of  one  part  first  quality  of  natural  hydraulic  cement, 
and  two  parts  of  clean,  coarse,  sharp  sand. 

The  quality  of  the  materials  furnished  was  excellent,  a  good 
quality  of  Rosendale  cement  being  used,  and  the  sand,  though  of  a 
dark-reddish  cast,  was  all  that  could  reasonably  be  desired. 

The  number  of  hands  employed  to  prepare  the  mortar  was  dis- 
tressingly inadequate. 

A  "  batch  "  of  the  mortar  consisted  of  one  barrel  of  cement  and 
two  barrels  of  sand.  An  empty  barrel  minus  both  heads  was  used 
for  measuring  the  sand. 

This  was  placed  upright  in  the  mortar  box  by  one  man,  while 
two  others  with  shovels  commenced  to  toss  sand  from  a  pile  about  ten 
feet  away,  presumably  with  the  intention  of  having  it  land  inside  of 
the  barrel ;  and  at  this  they  were  fairly  successful,  as  the  barrel  was 
soon  filled,  and  heaped  up  by  the  time  the  sand  which  did  not  land 
inside  the  barrel  had  accumulated  around  on  the  outside  nearly  half 
as  high  as  the  barrel  itself.  In  the  meantime  the  man  who  handled 
the  headless  barrel  was  wringing  and  twisting  in  a  desperate  effort  to 
empty  the  barrel  and  set  it  again,  during  which  time  there  was  no  let 
up  by  the  sand  tossers. 

They  worked  away  for  dear  life,  without  deigning  to  cast  even 
a  glance  at  the  man,  whom  the  author  expected  to  see  buried  alive. 

How  the  man  did  it  is  a  mystery,  but  certain  it  is  that  the  barrel 
was  finally  set  for  the  second  time,  and  the  man  emerged  from 
behind  the  sand  storm  looking  not  very  much  the  worse  for  wear. 


276  AMERICAN    CEMENTS. 

In  a  twinkling  the  barrel  was  again  heaped  up  and  running  over. 
Interest  in  the  project  now  became  absorbing,  and  the  author  walked 
around  on  the  opposite  side  to  get  a  better  view. 

The  instant  the  sand  tossers  had  dropped  their  shovels,  what 
before  had  appeared  to  be  unseemly  haste  had  become  a  whirlwind, 
but  the  author  was  not  left  long  in  doubt  as  to  the  cause  for  it. 

The  barrel  handler  had  learned  from  experience  that  he  had  no 
time  to  waste  in  meditation,  and  he  clasped  his  arms  around  the 
barrel  and  swayed  it  from  side  to  side,  and  back  and  forth,  working 
with  all  his  might  to  free  the  barrel  and  get  clear  of  the  mortar  box. 

And  well  he  might,  for  the  sand  tossers'were  upon  him. 

With  a  barrel  of  cement  between  them,  they  cast  it  upon  the 
pile  of  sand  in  the  mortar  box,  and  almost  before  it  had  landed  one  had 
knocked  a  head  in  with  the  edge  of  a  shovel,  while  the  other  had  up- 
set  it,  and  the  flying  cement  was  close  upon  the  heels  of  the  retreat- 
ing barrel  handler. 

But  his  turn  had  now  come,  and  quick  as  a  flash  he  had  grasped 
a  hose  and  was  turning  wate'r  upon  the  pile  of  sand,  cement,  and  men 
in  the  mortar  box. 

The  stream  struck  the  heap  of  sand  and  cement  just  as  the 
heels  of  the  sand  tossers  were  seen  emerging  from  it. 

Now  came  the  mixing.  No  hoes  were  used.  The  sand  tossers 
simply  turned  up  the  edge  of  the  sand  with  shovels,  while  the  barrel 
handler  held  the  hose  on  the  cement  in  the  center  of  the  pile  until 
the  mass  was  saturated. 

That  ended  the  mixing,  which  had  consumed  possibly  forty-five 
seconds  of  time,  and  the  sand  tossers  quickly  deposited  the  alleged 
mortar  in  another  box  which  was  swung  away  by  derrick  to  the 
masons  on  the  piers,  and  the  comedy  began  again. 

Occasionally  when  some  of  the  masons  happened  to  be  engaged 
in  setting  a  large  face  stone,  the  mortar  would  be  fairly  mixed,  but 
when  the  work  on  the  piers  was  mostly  backing,  then  indeed  were 
the  mortar  mixers  called  upon. 

With  so  small  a  mortar  crew,  for  so  many  masons,  it  was  simply 
out  of  the  question  to  produce  good  mortar. 

The  color  of  the  sand  and  cement  being  so  nearly  alike,  it  was 
easy  to  imagine,  by  those  who  wished  so  to  do,  that  the  materials 
were  fairly  well  mixed ;  while  the  facts  are  that  about  one  half  of  the 


AMERICAN   CEMENTS.  277 

sand  which  was  used  in  the  mortar  was  as  innocent  of  a  coating  of 
cement  as  when  it  laid  in  its  native  bed. 

Later  in  the  season  the  author  noted  the  pointing  of  the  finished 
piers  with  Portland  cement,  and  thus  was  hidden  from  sight  another 
instance  of  the  almost  criminal  folly  of  giving  out  such  work  by  con- 
tract to  the  lowest  bidder. 

No  more  pernicious  system  was  ever  devised. 

Several  years  ago  the  author,  who  manufactured  the  Rock  cement 
used,  had  occasion  to  witness  the  construction  of  some  stone-masonry 
piers  for  a  railroad  bridge  across  a  river  where  the  water  was  from 
40  to  50  ft.  deep,  and  the  current  was  very  strong. 

The  masonry  was  constructed  in  wooden  caissons,  which  were 
built  up  a  little  in  advance  of  the  masonry  work,  the  caissons  being 
gradually  sunk  to  their  foundations  by  the  weight  of  the  masonry. 

It  would  seem  that  if  there  ever  was  need  of  mortar  being  well 
made,  it  was  in  such  a  structure  as  the  one  under  consideration ;  but 
as  a  layer  of  stone  was  completed,  sand  was  sprinkled  over  it,  and  on 
top  of  this  was  sprinkled  some  cement,  and  a  hose  was  then  turned 
on  for  awhile,  whereupon  another  layer  of  stone  followed. 

There  was  not  the  slightest  pretense  of  mixing  the  cement  and 
sand  together,  and  yet  the  cost  of  this  bridge  was  over  one  million 
dollars,  and,  strange  to  relate,  it  still  stands. 

There  is  scarcely  a  year  passing  that  spring  freshets  do  not 
carry  away  many  bridges,  and  when  the  stone  piers  are  broken  and 
destroyed,  it  is  invariably  found  that  the  bedding  of  the  stones  is 
practically  clear  of  cement  mortar. 

There  is  but  one  cause  for  this  —  the  cement  and  sand  were 
never  properly  mixed  together. 

Had  they  been,  and  the  mixture  rendered  quite  plastic,  the  stones 
could  never  have  separated  from  the  mortar. 

As  well  pull  the  stones  apart  in  their  center  lines  as  at  the  joints. 

With  poorly  mixed  mortar,  the  weight  of  the  superstructure  and 
the  stones  themselves  is  all  that  prevents  the  bridge  from  moving 
down  stream  at  flood  time. 

Up  to  the  time  when  setting  commences,  cement  and  sand  cannot 
be  too  well  mixed. 

In  short,  if  the  mortar  is  treated  properly,  there  will  be  fewer 
bridges  moving  from  their  foundations  at  flood  time,  for  nothing  is 


278  AMERICAN    CEMENTS. 

more  certain  than  that  when  good  cement  is  used,  and  the  mortar  is 
worked  as  it  should  be,  a  bridge  pier  will  become  monolithic  in  char- 
acter, and  immovable  unless  carried  away  bodily. 

As  an  instance  of  the  result  of  a  proper  manipulation  of  natural 
hydraulic  cement  mortar,  attention  is  directed  to  page  13,  in  which 
reference  is  made  to  an  aqueduct  built  by  the  Carthaginians  over 
2,500  years  ago. 

From  the  top  of  this  aqueduct,  probably  through  seismic  dis- 
turbances, an  enormous  body  of  stone  masonry  was  dislodged,  falling 
over  100  ft.  upon  the  rocks  below,  where  it  still  lies  unbroken,  a 
silent  but  powerful  argument  in  favor  of  thoroughly  honest  work  in 
the  preparation  of  cement  mortars. 

A  RARE  COLLECTION. 

In  the  author's  collection  of  ancient  mortars  and  concretes,  a 
few  specimens,  with  the  probable  dates  of  their  fabrication,  are  noted 
as  worthy  of  mention. 

GERMANY. 

Bonn.  —  Mortar  from  the  Cathedral  at  Bonn  on  the  Rhine,  con- 
structed in  the  fourth  century.  Sample  exceedingly  hard. 

Coblenz.  — •  Mortar  from  the  Kaufaus  overlooking  the  Moselle, 

1688. 

FRANCE. 

Paris.  —  Mortars  from  the  Catacombs,  1786;  from  the  Arc  de 
Triomphe  de  1'Etoile,  1 806 ;  and  from  the  staircase  in  the  Louvre,  1541. 

Versailles. —  Mortar  from  one  of  the  cottages  in  the  garden  of 
the  Petit  Trianon.  Time  of  Louis  XVI. 

ENGLAND. 

Oxford.  —  Mortars  from  the  old  city  walls  at  New  College,  1370 ; 
from  the  Carfax  Tower,  1327  ;  from  an  old  stone  gateway  leading  to 
St.  Mary's  College,  1437;  from  St.  Magdalen  College,  1475;  from 
Wadham  College,  1610;  from  columns  of  Christ  Church,  1180; 
from  the  battlements  of  New  College,  1386.  The  latter  is  a  fine 
specimen  of  a  hard  and  durable  concrete. 

Warwick.  — •  Mortar  from  the  entrance  gate  to  Warwick  Castle, 
91 5  ;  firm  and  hard.  Mortar  from  Guy's  Tower,  Warwick  Castle,  1394- 

Windermere.  —  Mortar  from  the  ruins  of  a  tower  formerly  occu- 
pied by  monks,  opposite  Bowness,  Lake  Windermere. 


AMERICAN    CEMENTS. 


279 


Kenilworth.  —  Mortars  from  the  ruins  of  Kenilworth  Castle,  and 
from  the  south  side  of  the  "  Old  Norman  Keep,"  also  from  the  in- 
terior "  Norman  Court,"  twelfth  century. 

London.  —  Mortar  from  the  main  banqueting  hall  in  the  main 
tower  of  the  "  Tower  of  London."  A  fine  sample  of  mortar  from  one 
of  the  passageways  in  the  "  Tower  of  London."  This  tower  was 
founded  by  William  the  Conqueror.  Mortar  from  the  stairway  lead- 
ing to  the  tomb  of  Henry  VII.,  Westminster  Abbey.  Time  of 
Edward  I.,  Edward  II.,  Edward  III.,  and  Henry  VII.  Mortar  and 
stone  from  the  monument  erected  by  Sir  Christopher  Wren  to  com- 
memorate the  great  London  fire  of  1666.  The  stones  for  this  monu- 
ment were  quarried  at  Portland,  on  the  south  coast  of  England.  It 
was  the  color  of  this  stone  which  suggested  the  name  for  artificial 
cement  (see  page  18). 

SCOTLAND. 

Edinburgh.  —  Mortar  from  St.  Anthony's  Chapel,  a  ruin  near 
Edinburgh;  dark  colored  and  exceedingly  hard  and  firm;  1435. 
Mortar  from  an  old  chapel  situated  at  Edinburgh  Castle.  Mortar 
from  a  room  in  which  the  seventh  Duke  of  Argyle  was  imprisoned 
at  Edinburgh  Castle.  Mortar  from  the  abbey  at  Holywood  Palace, 
1128. 

Dunkeld.  —  A  piece  of  stone  and  mortar  from  the  walls  of  the 
partially  ruined  cathedral  at  Dunkeld,  taken  from  a  point  near 
which  rests  a  carved  figure  of  the  "  Wolf  of  Badenoch  "  recumbent 
and  in  full  armor.  This  figure  is  one  of  the  few  which  survived  the 
destruction  of  the  ruin.  The  "  Wolf  of  Badenoch  "  belonged  to  the 
"  Clan  of  Cumin."  Time,  twelfth  century. 

Fort  William.  —  Exceedingly  hard  and  firm  concrete  from  the 
ruins  of  Inverlochy  Castle.  Formerly  the  property  of  "  The  Black 
Cumin  "  of  the  "  Cumin  Clan."  Time,  thirteenth  century. 

Kingussie.  —  Mortar  from  the  ruins  of  Ruthven  Castle.  For- 
merly the  property  of  the  "  Red  Cumin "  of  the  "  Cumin  Clan." 
Time,  thirteenth  century. 

Stirling.  —  A  hard  and  heavy  concrete  from  the  wall  surround- 
ing Stirling  Castle.  Time,  James  III.  to  James  V. 

ITALY. 
Rome.  —  Mortars  from  the  walls  in  the  Appian  Way,  from  the 


280  AMERICAN    CEMENTS. 

Catacombs,  from  the  Coliseum,  and  from  the  old   Roman  Forum; 
also  a  fine  specimen  of  Pozzuolana. 

UNITED  STATES. 

Nebraska. —  Mortar  from  a  prehistoric  stone  wall  surrounding 
several  acres  of  level  land  on  a  prominence  about  twenty  miles  south- 
west of  Chadron.  This  mortar  is  somewhat  friable,  but  it  is  well 
calculated  to  resist  the  effects  of  the  extremes  of  temperature  preva- 
lent in  that  climate,  as  it  bears  no  evidences  of  disintegration. 

Indiana.  —  Samples  of  artificial  stone  produced  in  Posey  County, 
by  the  prehistoric  race  known  as  the  "  Mound-Builders,"  in  the 
manner  described  on  pages  44  to  49,  also  in  this  chapter. 

THOUGHTS  ON  STONE-MAKING. 

And  this  our  life,  exempt  from  public  haunt, 

Finds  tongues  in  trees,  books  in  the  running  brooks, 

Sermons  in  stones,  and  good  in  everything.  — Shakespeare. 

He  builded  better  than  he  knew ; 

The  conscious  stone  to  beauty  grew.  —  Emerson. 

On  the  desk  at  which  the  author  is  sitting  while  he  pens  these 
lines  there  rests  three  fine  specimens  of  stones.  They  are  very  similar 
in  composition,  yet  wholly  unlike  in  the  manner  of  their  creation; 
and  as  they  either  directly  or  indirectly  relate  to  hydraulic  cement, 
we  venture  upon  a  brief  dissertation,  trusting  that  it  may  not  prove 
entirely  devoid  of  interest. 

Taking  down  the  first  specimen,  we  examine  it  as  we  have  done 
many  times  before,  yet  always  with  curious  interest,  for  it  seems  impos- 
sible to  hold  it  in  one's  hand  for  examination  without  wondering  what 
can  be  its  true  history.  It  is  but  one  of  hundreds  of  this  kind  of  stones 
in  the  collection  of  the  author.  Its  hardness  was  caused  by  natural 
infiltration  and  subsequent  evaporation  of  water  charged  with  calcium 
carbonate  in  solution,  through  clay  beds  which  had  become  cracked  in 
all  directions  by  shrinkage  due  to  exposure  to  the  direct  rays  of  the 
sun.  The  seams  thus  produced  became  filled  with  nearly  pure  calcium 
carbonate  much  darker  in  color  than  the  main  .body  of  the  stones. 

These  stones  represent,  then,  what  was  at  one  time  a  single  sheet 
of  petrified  mud,  which  was  broken  up  by  the  ice  floe,  the  resultant 
blocks  becoming  rounded  by  abrasion,  or  attrition  caused  by  moving 


AMERICAN    CEMENTS.  281 

waters  or  ice,  or  by  surface  decomposition.  They  were  carried  along 
and  deposited  during  one  of  the  glacial  periods,  and  are  now  found 
in  a  drift  of  shale  i  5  to  25  ft.  below  the  surface. 

The  shale  occurs  at  a  bend  of  a  rapid  stream  in  the  town  of 
Alden,  Erie  County,  N.  Y.  During  the  spring  freshets  the  stream, 
which  at  this  point  has  an  impact  of  at  least  1,600  Ibs.  per  square 
foot,  undermines  the  shale  and  deposits  the  specimens  along  the 
river  bed.  In  the  summer  the  water  falls,  and  specimens  varying 
in  weight  from  3  to  100  Ibs.  may  be  readily  secured. 

This  beautiful  specimen,  then,  which  we  now  hold  in  our  hand, 
did  not  assume  its  present  form  and  comeliness  when  the  world  was 
young.  Ages  may  have  elapsed  during  the  time  when  it  was  in  a  state 
of  mud.  It  may  have  lain  for  countless  centuries  in  this  condition  at 
the  bottom  of  some  vast  inland  sea,  and  ages  upon  ages  must  have 
passed  before  the  slow  uplifting  of  the  land  exposed  the  mud  to  the 
direct  rays  of  the  sun.  Then  came  the  almost  interminable  length 
of  time  when  the  mud  would  be  exposed  alternately  to  water  and 
sunshine.  Finally  there  came  the  complete  drying  out  with  the  re- 
sultant checks  and  cracks.  Next  there  was  required  a  body  of  water 
charged  with  calcium  carbonate  in  solution,  and  the  mud  had  to  be 
alternately  saturated  with  this  "  hard  "  water  and  subjected  to  the 
sun's  rays.  Thus  slowly  the  mud  became  petrified.  Then,  how 
much  time  must  have  elapsed  after  this  before  it  was  disturbed  and 
broken  up,  and  how  far  did  it  travel  before  it  found  its  resting  place 
in  the  shale  bank  ?  And  how  long  did  it  lie  there  before  it  was 
again  disturbed  by  the  stream  which  disclosed  it  to  the  author?  Thus 
the  world  was  not  young  when  this  specimen  finally  assumed  its 
present  form.  But  long  as  the  time  may  seem  since  the  mud  was 
deposited  on  the  bottom  of  the  sea,  it  was  but  a  day  as  compared 
with  its  existence  previous  to  that  time. 

Let  us  go  back  to  the  time  when  this  mud  was  part  and  parcel  of 
some  lofty  granite  cliff,  perhaps  forming  the  crown  to  some  vast  moun- 
tain peak.  Who  can  tell  how  long  it  stood  thus  under  the  full  rays  of 
the  sun,  or  the  pitiless  rain  beating  down  upon  it,  bearing  the  great 
rock  destroyer  as  well  as  maker,  carbon  dioxide  gas,  which  sought  out 
its  interstices  and  inaugurated  the  work  of  decay  and  disintegration, 
which  never  rested,  until  finally  the  granite  crumbled,  decomposed, 
and  was  carried  down  by  the  rains  to  the  streams  and  rivers,  the 


282  AMEPICAN    CEMENTS. 

feldspar  giving  up  its  potash,  soda,  or  lime  to  the  great  destroyer, 
leaving  behind  only  mud  ?  The  quartz,  in  the  meantime,  had  suc- 
cumbed and  turned  to  sand,  while  the  mica,  following  the  fate  of  the 
feldspar,  gave  up  its  potash,  oxides  of  iron,  or  magnesia,  as  the  case 
may  be,  thus  leaving  the  silica  and  alumina  to  become  clay  mud. 

And  now  let  us  take  one  more  look  backward,  and  imagine,  if 
we  can,  the  existence  of  this  material  before  it  became  granite. 

Was  it  thrown  up  in  the  manner  of  igneous  rocks,  in  a  molten  or 
plastic  state  ?  And  when  the  rain  fell  upon  it,  thus  providing  the 
water  of  crystallization,  the  latter  taking  place  as  soon  as  the  material 
was  sufficiently  cooled  ?  And  if  so,  how  long  was  the  material  held 
in  a  molten  or  plastic  state  ?  What  was  its  condition  before  it  be- 
came molten  or  plastic  ?  Or,  was  the  material  a  bed  of  clay  or  mud, 
which  became  subject  to  metamorphic  action,  and  thus  became 
slowly  converted  into  granite  ? 

How  many  times  have  the  rocks  in  the  hills  beside  the  roadways, 
which  we  see  daily,  but  upon  which  we  scarcely  bestow  a  thought, 
been  converted  from  rocks  to  mud,  and  from  mud  to  rocks,  since  the 
days  when  the  world  was  young  ? 

And  now  we  reluctantly  return  this  most  interesting  bit  of  stone 
to  its  accustomed  place,  and  with  a  feeling  of  awe  and  veneration  we 
take  the  next  specimen  into  our  hands. 

My  fingers  press  the  places  that  once  were  pressed  by  the  fingers 
of  the  Mound-Builder,  who  formed  it  and  molded  it,  and  turned  the 
plastic  clay  into  stone. 

On  a  summer's  day,  under  wide-spreading  branches,  by  the  bank 
of  a  stream,  with  his  wife  and  children  about  him,  the  Mound- 
Builder  sits  and  "  finds  tongues  in  trees,  and  books  in  the  running 
brooks,"  as  he  molds  the  plastic  clay  into  the  forms  then  prevalent 
for  domestic  use. 

Now  he  arises,  and  with  a  stone  pail  of  his  own  creation  in  his 
hand,  goes  down  to  the  spring  of  "  hard  "  water,  and  returning,  he 
gently  sprinkles  the  molded  vessels  which,  by  a  retention  of  the  cal- 
cium carbonate,  gradually  becomes  hardened,  as  the  process  is 
repeated  day  after  day. 

Was  this  really  the  first  lesson  in  the  art  of  hydraulic  cement 
fabrication?  or  was  the  process  an  old  one  handed  down  for  hundreds 
or  thousands  of  years  ? 


AMERICAN    CEMENTS.  283 

At  all  events,  it  is  quite  true  that  "  it  is  not  alone  in  Europe  that 
we  find  a  well-founded  claim  of  high  antiquity  for  the  art  of  making 
hard  and  durable  stone  by  a  mixture  of  clay,  lime,  and  sand." 

It  seems  hardly  credible  that  the  Mound-Builders  could  have 
been  possessed  of  the  knowledge  necessary  to  have  enabled  them  to 
observe  the  processes  of  nature  in  the  conversion  of  mud  flats  into 
hard  and  durable  stones  as  already  described. 

Admitting,  however,  as  we  are  forced  to  do,  that  they  did 
observe  and  did  understand  this  transformation,  how  are  we  to 
withhold  our  profound  admiration  for  their  truly  scientific  attain- 
ments as  shown  in  their  ability  to  produce,  artificially,  the  same  results  ? 

Truly  there  must  have  been  men  of  ability  in  those  days  long 
dead,  and  artists  as  well,  for  who  among  us  of  to-day  can  excel  them 
in  the  construction  of  vessels  one  eighth  of  an  inch  thick,  and  able 
to  withstand  heat  as  described  on  page  45  ?  or  the  construction  of 
such  vessels  5  or  6  ft.  in  diameter  as  described  on  page  44  ? 

Indeed,  the  principle  involved  in  the  operation  is  practically 
unknown  to  the  people  of  to-day. 

When  we  think  of  the  people  "  who  inhabited  this  continent  at 
a  period  so  remote  that  neither  tradition  nor  history  can  furnish  any 
account  of  them,"  we  are  led  to  reflect  that  it  may  be  only  a  question 
of  time  when  people,  in  speaking  of  the  present  age,  will  refer  to  us 
as  a  race  of  half -civilized  tombstone-builders. 

These  people  are  known  to  us  only  as  a  race  of  "  mound- 
builders,"  when  the  mounds  they  built  were  simply  the  graves  of 
their  dead  over  which  the  earth  was  raised  to  mark  the  place  of 
burial,  while  we  at  the  present  time  place  a  stone  to  mark  the  spot. 

And  it  is  clearly  evident,  if  we  are  to  judge  by  the  appearance 
of  the  latter  in  the  old  burial  places  throughout  New  England,  that 
the  mounds,  if  left  undisturbed,  will  far  outlast  any  stone  that  may 
be  raised  for  the  purpose. 

Therefore,  in  so  far  as  relates  to  the  permanency  of  burial 
marks,  we  are  a  long  way  behind  the  unknown  race  who  occupied 
this  continent  long  before  the  advent  of  the  red  man.  How  long  be- 
fore is  unknown.  It  is  even  unknown  as  to  the  time  when  the  race 
of  Mound-Builders  became  extinct.  It  is  not  altogether  improbable 
that  some  of  the  blood  of  the  Mound-Builders  may  still  be  coursing 
in  the  veins  of  the  red  man. 


284  AMERICAN    CEMENTS. 

The  system  of  government  established  and  maintained  by  the 
Five  Nations  of  the  State  of  New  York,  and  which  was  known  to 
have  been  in  existence  over  one  hundred  years,  and  how  much  longer 
is  unknown,  before  the  landing  of  the  Pilgrims  at  Plymouth  Rock, 
measured  by  its  utility  was  not  inferior  to  any  system  established  by 
the  Puritans,  or  any  known  system  of  government  in  Europe  at  that  time. 

Those  who  study  the  history  and  lives  of  the  races  which  once 
occupied  our  land  do  not  readily  fall  into  the  common  error  of  be- 
lieving that  all  was  ignorance  and  barbarism  which  preceded  the  ad- 
vent of  the  Puritan. 

Reverently  we  lay  down  this  piece  of  stone,  this  relic  of  days 
long  gone  by,  with  a  feeling  akin  to  the  warmest  admiration  and 
kindliest  friendship  for  the  man  whose  hands  fashioned  and  held  it 
up  for  approval. 

The  centuries  which  have  elapsed  since  he  held  it  as  I  now  hold 
it  seem  as  but  a  day.  His  workmanship  proves  that  he  was  every  inch 
a  man,  and  I  hold  out  my  hand  to  grasp  his  across  the  abyss  of  time. 

We  come  now  to  our  third  specimen.  It  is  merely  a  fragment 
of  hydraulic  cement  stone,  yet  it  contains  within  its  mysterious  body 
many  a  long,  and  ofttimes  tedious  sermon. 

As  we  take  it  down  and  examine  it,  perhaps  for  the  hundredth 
time,  under  a  strong  glass,  we  can  never  restore  it  to  its  place  with- 
out a  thought  as  to  its  wonderful  construction. 

It  is  but  a  limestone,  called  by  geologists  an  "  impure  lime- 
stone," which  expression  can  be  and  is  used  to  cover  numberless 
variations  in  the  percentages  of  impurities  which  it  may  contain. 

Absolutely  pure  limestone  is  practically  unknown.  It  is  a  very 
pure  limestone  which  does  not  contain  more  than  3  to  5  per  cent,  of 
impurities. 

The  specimen  before  us  contains  about  30  per  cent,  of  impuri- 
ties, and  it  is  this  amount  which  determines  its  classification  under 
the  head  of  hydraulic  cement  stones.  With  one  half  the  impurities 
named  present,  it  would  have  been  classed  as  an  hydraulic  limestone. 

It  is  to  be  understood  that  the  impurities  in  this  case  consist 
principally  of  clay. 

How  does  it  come  about  that  a  limestone  may  contain  30  per  cent. 
of  clay  ?  We  will  find,  if  we  take  the  limestones  as  a  mass,  that  not  one 
cubic  yard  in  ten  thousand  will  contain  clay  to  the  extent  of  30  per  cent. 


AMERICAN    CEMENTS.  285 

Hydraulic  cement  rock,  then,  is.  not  so  common  a  mineral  as 
many  would  suppose.  The  beds  of  limestone,  which  fall  below  the 
requisite  amount  of  clay  to  constitute  a  good  cement  rock,  are  prac- 
tically limitless. 

It  will  be  observed  by  those  who  take  an  interest  in  the  study  of 
rocks,  that  in  a  majority  of  cases,  where  cement  rocks  occur,  they  are 
found  to  lie  underneath  several  layers  of  limestone  which  vary  from 
practically  pure  strata  at  the  top  to  hydraulic  limestone  as  we  ap- 
proach the  cement  rock  in  the  descending  order. 

It  is  a  rule  that  in  a  deposit  of  impure  limestone,  while  the  lower 
layer  may  contain  a  percentage  of  clay  which  renders  it  eminently 
hydraulic,  the  next  layer  above  may  contain  a  trifle  less  clay,  and  so 
on  to  the  upper  layer,  which  may  be  practically  a  pure  limestone. 

How  are  we  to  account  for  these  facts  ?  There  is  but  one  way 
that  is  at  all  clear  or  conclusive  to  the  author,  and  it  may  be  said  in 
passing,  that  his  conclusions  are  not  in  full  accord  with  the  higher 
authorities  on  this  subject. 

The  question  is,  then,  in  what  manner  are  the  calcium  carbonate 
and  the  clay  intermingled  in  an  hydraulic  cement  rock? 

The  process  of  intermingling  these  two  ingredients  in  the  first 
specimen  has  been  shown  to  be  by  infiltration ;  but  that  process  will 
not  satisfy  the  conditions  in  a  cement  rock,  for  it  must  be  clear  that 
by  the  process  of  infiltration  the  amount  of  carbonate  of  lime  must 
be  limited  to  the  voids  or  interstices  in  the  clay,  which  do  not  form 
one  fourth  of  its  volume ;  whereas,  in  a  cement  rock,  the  amount  of 
carbonate  of  lime  must  reach  as  high  as  70  to  75  per  cent,  of  the  en- 
tire volume. 

It  is  well  known  that  limestones  are  always  deposited  in  water, 
and  in  a  vast  majority  of  cases,  in  sea  water.  Clay  beds  also  are 
deposited  in  water,  but  are  subject  to  subsequent  drift. 

Now  if  we  take  a  lump  of  clay  and  drop  it  in  a  glass  of  water, 
leaving  it  undisturbed  for  a  few  days,  it  will  be  found,  if  the  clay  is 
pure,  that  it  will  have  become  settled  in  the  bottom  of  the  glass,  leav- 
ing the  water  practically  clear. 

But  should  the  clay  contain  a  small  percentage  of  soda  or 
potash,  it  will  not  settle  down  so  readily.  In  fact,  it  will  be  held 
more  or  less  in  solution,  the  water  remaining  in  a  muddy  condition. 

If    now   we   state   the   further   fact  that   of   the    hundreds   of 


286  AMERICAN    CEMENTS. 

analyses  of  Rock  cements  and  cement  rocks  which  are  familiar  to  the 
author  not  one  thus  far  has  been  found  where  the  clay  portion  did 
not  contain  a  small  percentage  of  one  or  the  other,  and  in  most  in- 
stances both  of  the  alkalies  named,  the  way  will  have  become  cleared 
for  an  easy  understanding  of  what  is  to  follow. 

It  is  well  understood  that  water  will  hold  calcium  carbonate  in 
solution  indefinitely,  or  until  it  is  surcharged,  in  which  case  it  will  be 
precipitated.  This  is  noticeable  when  hard  water  is  boiled  in  a  tea- 
kettle, or  when  used  as  feed  water  for  steam  boilers. 

In  these  instances  the  volume  of  water  being  reduced,  it  be- 
comes surcharged,  and  the  carbonate  of  lime  falls  to  the  bottom. 
The  same  result  will  follow  if,  instead  of  the  volume  of  water  being 
reduced,  the  quantity  of  carbonate  of  lime  is  increased. 

It  is  the  latter  condition  which  prevails  when  the  deposition  of 
calcium  carbonate  takes  place  in  the  formation  of  large  bodies  of 
limestone,  and  when  the  water  is  pure,  or  practically  so,  the  deposi- 
tion will  become  what  is  called  pure  limestone. 

But  when  clay  is  held  in  solution  in  the  water,  the  atoms  of  cal- 
cium carbonate,  in  falling  down,  will  become  coated  with  the  clay 
through  which  it  passes,  and  thus  we  have  impure  limestone,  the 
amount  of  the  clay  in  solution  governing  the  percentage  of  clay  found 
in  the  stone  and  thus  is  determined  whether  the  stone  becomes 
eminently  hydraulic  cement  stone  or  hydraulic  limestone. 

It  is  thus  that  the  lower  layer  usually  contains  more  clay  than  the 
layer  next  above;  and  so,  as  the  calcium  carbonate  falls,  carrying  down 
the  clay,  the  latter  becomes  less  in  quantity  in  the  succeeding  layers, 
until,  if  the  deposition  of  calcium  carbonate  continues,  and  there  is  no 
new  influx  of  clay,  the  layers  will  become  practically  pure  limestone. 

Instances  occur  where  a  layer  of  cement  rock  may  contain  a 
trifle  more  of  clay  than  the  layer  next  below.  This  is  caused  by  a 
temporary  influx  of  more  clay,  but  it  is  exceptional. 

There  are  instances  where  the  clay  is  in  excess  in  cement  rock 
throughout  the  formation.  In  these  instances  the  clay  carries  quite 
a  large  percentage  of  the  alkalies. 

Where  the  Lower  Silurian  limestone  formations  rest  directly 
upon  the  Potsdam  sandstone  the  lower  layers  usually  contain  sand. 
In  some  instances  it  is  so  excessive  as  to  cause  the  formations  to  be 
called  "  calcif erous  sandstone  " :  but  whenever  there  is  found  a  bed 


UNIVERSITY 

AMERICAN   CEMENTS^ 


of  clay  lying  between  the  Potsdam  and  the  limestone,  then  the  lower 
layers  of  limestone  are  found  to  be  hydraulic  in  character. 

And  thus  it  is  in  all  the  known  cement  rock  formations,  either 
clay  or  clay  shale  lies  underneath ;  and  the  same  quality  and  kind  of 
clay  is  found  in  and  throughout  the  cement  rock,  thus  proving  con- 
clusively, to  the  author  at  least,  that  first  came  the  clay,  a  portion  of 
which  was  deposited  and  a  portion  remaining  in  solution  in  the 
water,  due,  as  we  have  stated,  to  the  presence  of  soda  or  potash; 
then  came  the  carbonate  of  lime,  which  in  its  deposition  carried 
down  a  coating  of  clay  ;  and  thus  was  provided  by  nature  for  the  use 
of  man  one  of  his  most  valuable  building  materials. 

In  restoring  this  our  third  specimen  to  its  place,  we  note  its  fine- 
ness of  texture,  and  this  suggests  the  thought  as  to  the  size  of  the 
atoms  of  calcium  carbonate  when  held  in  solution,  which  are  so  small 
as  to  be  invisible  to  the  naked  eye. 

When  we  consider  these  minute  particles  as  being  coated  with 
clay,  and  thus  being  formed  into  compact  cement  stone,  we  come  to 
realize  the  difficulties  encountered  in  the  attempt  to  imitate  the 
physical  condition  of  this  material  in  the  preparation  of  the  same 
ingredients  for  artificial  cements. 

STATISTICS. 

From  the  year  1818,  when  the  Rock  cement  industry  was  first 
established  in  this  country,  until  1882,  no  public  statistics  were  kept 
to  show  the  extent  and  growth  of  this  branch  of  the  building  trade. 

Since  1882,  however,  such  records  have  been  faithfully  kept  by 
the  United  States  Geological  Survey,  Washington,  D.  C,  and  have 
been  published  yearly  in  Mineral  Resources  of  the  United  States, 
which  is  issued  by  the  Survey. 

The  author  has  prepared  several  of  these  yearly  reports,  and, 
having  a  natural  taste  in  that  direction,  he  has  let  no  opportunity 
pass  to  add  to  his  little  storehouse  of  knowledge  concerning  the 
statistics  of  the  Rock  cement  industry  from  the  date  of  its  birth  in 
this  country  near  the  little  village  of  Fayetteville,  in  Onondaga 
County,  N.  Y.,  in  the  year  1818  until  the  present  time. 

During  the  past  thirty  years  the  author  has  been  adding  little  by 
little  to  the  items  bearing  on  this  subject,  either  by  correspondence 
or  in  conversation  with  the  oldest  persons  engaged  in  the  industry, 


288 


AMERICAN    CEMENTS. 


by  gathering  bits  of  family  history,  and  in  ways  too  numerous  and 
uninteresting  to  record. 

The  difficulties  encountered  in  the  compilation  of  these  statistics 
during  the  period  named  have  been  much  greater  than  would  readily 
be  believed  by  a  person  who  has  never  attempted  such  work. 

Information  seemingly  reliable  would  accumulate  in  the  course  of 
years,  and  be  found  at  last  to  bear  but  a  slight  resemblance  to  the  truth. 

But  by  dint  of  persistent  effort  and  careful  gleaning  and  sifting, 
the  author  has  been  enabled  to  form  a  table  covering  the  entire 
history  of  the  industry  in  this  country,  which  he  feels  assured  will  be 
accepted  as  being  practically"  accurate,  and  in  the  entire  absence  of 
any  other  known  effort  in  the  same  direction,  authoritative. 

Production  of  Rock  cement  in  the  United  States  during  the 
time  since  the  industry  was  established  in  1818  to  Jan.  i,  1897. 


TIME. 

Years. 

No.  of  barrels. 

To  1830 

I  2 

300  ooo 

To  1840  .  . 

TO 

I,OOO,OOO 

To  1850 

IO 

A  2  CO  OOO 

To  1860  

IO 

I  I,OOO,OOO 

To  1870 

IO 

1  6  420  ooo 

To  1880  

IO 

22,OOO,OOO 

1880  

2,O3O,OOO 

1881  .  . 

2,4.4.O,OOO 

1882  

3,  16?,  ooo 

1883  , 

4  .IQO.OOO 

1884  , 

4,000,000 

1881; 

4,100,000 

1886 

4l86  I  ?2 

1887  

6,602,744. 

1888  

6,2;3,2QC 

1880 

6.01.876 

1800  . 

7,082,204 

1891  

7,4.  C  I,  C^; 

1802  . 

8,211,  181 

1803  , 

7,4.1  1,81-1; 

1  804.  ,                .... 

7,563,488 

i8oc  , 

7,74.1,077 

1  896            . 

7.070,  4.  CO 

Totals  .    

7Q 

I  CI,QQO,8l7 

AMERICAN    CEMENTS. 


289 


The  following  table  gives  the  number  of  barrels  of  Portland 
cement  imported  into  the  United  States,  and  the  number  of  barrels 
of  that  class  of  cement  manufactured  in  this  country  during  the  years 
named. 


YEARS. 

Imported. 

Domestic. 

!878   

92,OOO 

28,OOO 

1870 

IO6,OOO 

39,OOO 

1880   .    

l87,OOO 

42.OOO 

1  88  1  

22I,OOO 

6o,OOO 

1882   

370,406 

85,OOO 

1883  

486,418 

9O,OOO 

1884   

181,768 

IOO,OOO 

1885     

114,396 

I  5O,OOO 

1886     

6lO,O32 

I  5O,OOO 

1887  .      

1,070,4.00 

2?O,OOO 

1888     

i,  831,  104. 

25O,OOO 

1889  . 

1,740,356 

3OO,OOO 

1890   

1,04.0,186 

331,OOO 

1801  . 

2,088,313 

4  14,8  1  3 

1802  . 

2,4.4.0,614. 

14.7,4.40 

i  Sen  . 

2,  674.,  1  4.0 

190,612 

1804.  . 

2,63S,IO7 

798,717 

1  80;  . 

2,QQ7,3Q1 

990,324 

1896  . 

2,0,80,107 

1,14^,02'? 

Total          .    ... 

26,1:67,681 

6,804,009 

290  AMERICAN    CEMENTS. 

PRODUCT    OF    ROCK     CEMENT     IN     UNITED    STATES,    1895    AND    1896. 


STATE. 

1895. 

1896. 

"o 

U 

|l 

No.  of 
Barrels. 

Bulk 
Value 
at 

Mills. 

Number  of 
works 

No.  of 
Barrels. 

Bulk 
Value 
at 
Mills. 

Georgia.     .     .     . 
Illinois  .... 
Ind.  and  Ky.  .     . 
Kansas  .... 
Md.  and  W.  Va.  . 
Minnesota  .     .     . 
New  Mexico   .     . 
New  York  .     .     . 
Erie  County    .     . 
Onondaga    )    r 
Schoharie    \ 
Ulster  County     . 
Ohio  

I 
2 

14 
2 

4 

2 
I 

4 

10 

15 
3 
5 
i 

2 

I 

~67 

8,050 
491,012 
1,703,000 
140,000 
242,000 
73,772 
5,OOO 

556,754 
152,973 

3,230,000 
38,C60 
600,895 
10,000 

13,050 
476,511 

$6,038 
171,854 
68l,400 
56,000 
Il6,700 
33,621 
6,OOO 

269,089 

77,974 

1,938,031 
22,836 

300,447 
1  7,000 
7,830 
190,604 

I 
2 

15 

2 

5 

2 
I 

4 

10 

15 

6 

i 

3 

i 

12,700 
544,326 
1,636,000 
125,567 
271,500 
83,098 

idle 

550,851 
204,375 
3,426,692 
28,565 
608,000 

I  2,000 
16,776 
450,000 

$9,525 
217,731 
654,400 
50,226 
125,175 
38,549 

275,426 
92,450 
2,056,015 

17,139 
304,000 
18,000 
10,566 
l8o,000 

Pennsylvania  .     . 
Texas     .... 
Virginia      .     .     . 
Wisconsin  .     .     .. 

Total  .     .     . 

7,741,077 

$3,895,424 

7i 

7,970,450 

$4,049,202 

The  foregoing  tables  afford  a  wide  field  for  speculation  as  to 
the  uses  to  which  this  enormous  amount  of  cement  has  been  applied. 

One  can  hardly  realize  the  value  of  the  properties  which  have 
been  constructed  with  mortars  and  concretes  made  with  this  cement. 

Among  those  which  seem  most  prominent  to  the  mind  may  be 
mentioned  the  almost  innumerable  number  of  tunnels,  bridges,  cul- 
verts, and  buildings  connected  with  the  235,000  miles  of  railroad 
track  in  this  country,  the  improvements  made  in  all  cities  in  the 
line  of  waterworks,  in  the  construction  of  aqueducts,  reservoirs,  and 
dams,  and  in  the  street  pavements,  concrete  foundations,  sewers,  and 
sidewalks. 

The  amount  of  American  Rock  cement  which  has  been  used  in 
the  construction  of  cisterns  by  the  farmers  and  planters  of  this  coun- 
try, and  in  the  villages  having  no  waterworks,  is  almost  inconceivable. 


AMERICAN    CEMENTS.  291 

We  append  hereto  a  list  of  a  few  of  the  notable  engineering 
and  architectural  structures  which  have  been  laid  in  American  Rock 
cement. 

It  is  difficult,  if  not  impossible,  to  estimate  the  cost  of  these 
improvements,  the  permanence  and  stability  of  which  depend  so 
much  on  the  cement  used  in  their  construction. 

Important  as  these  structures  may  be,  they  are  absolutely  insig- 
nificant when  compared  with  the  immense  body  of  work  done  with 
American  Rock  cements,  of  which  no  complete  record  can  ever  be 
made. 

STRUCTURES  LAID   IN  AMERICAN   ROCK    CEMENT. 

CUMBERLAND,  MD.,  CEMENT. 

Washington,  D.  C.  —  Boundary  Sewer,  Bureau  of  Engraving 
and  Printing,  New  Patent  Office,  National  Museum,  New  Pension 
Office,  New  Navy,  State,  and  War  Department,  New  Library  Build- 
ing, Tiber  Sewer. 

Federal  Buildings.  —  Pittsburgh  and  Harrisburg,  Penn.,  Balti- 
more, Md. 

U.  S.  Government  Work. —  Kanawha  River  Locks,  W.  Va. 

Bridges  in  Pennsylvania. — Altoona,  Columbia,  Harrisburg, 
Millersburgh,  Johnstown,  Williamsport. 

Centennial  Buildings  in  Philadelphia,  Penn.,  and  Johns  Hop- 
kins Hospital  Building,  Baltimore,  Md. 

ROUND  TOP  CEMENT,  HANCOCK,  MD. 

Washington,  D.  C.  —  United  States  Capitol,  Washington  Monu- 
ment, War,  State,  and  Navy  Building,  Washington  and  Potomac 
Tunnel,  New  Washington  Reservoir,  Boundary  Sewer  2^  miles 
long,  20  ft.  internal  diameter,  Long  Bridge  over  the  Potomac 
River,  and  Cabin  John  Bridge,  which  is  the  largest  stone  arch  in 
existence.  It  was  built  by  General  Meigs  in  1866,  and  has  one  span 
of  220  ft.,  with  a  rise  of  57  ft.  3  ins.,  and  is  20  ft.  wide.  This 
bridge  is  only  exceeded  in  the  world's  history  by  a  bridge  built  in 
1377  by  Barnabo  Visconti  over  the  Adda  at  Frezzo,  Italy,  which 
was  destroyed  in  a  local  war  in  1416.  It  was  a  segmental  arch,  with 
a  span  of  237  ft.  and  a  rise  of  68  ft. 


292  AMERICAN    CEMENTS. 

Baltimore,  Md.  —  Gunpowder  Waterworks,  City  Hall  Building, 
Gas  Works. 

HOWARD  CEMENT,  CEMENT,  GA. 

Two  bridges  across  Tennessee  River  at  Chattanooga,  Tenn.; 
Kimball  House,  Atlanta,  Ga. ;  Georgia  Central  Railroad  Bridge  at 
Columbus,  Ga. ;  Fulton  County  Jail  and  Seaboard  Air  Line  Depot, 
Atlanta,  Ga. ;  Times  Building,  Chattanooga,  Tenn. ;  the  Vanderbilt 
residence,  Biltmore,  Asheville,  N.  C. 


JAMES  RIVER  CEMENT,  GLASGOW,  VA. 

Waterworks  in  Virginia. —  Richmond,  Lynchburgh,  Staunton, 
Charlottesville,  Liberty,  Lexington,  Danville,  also  in  Durham,  N.  C. 

Richmond,  Va. —  New  City  Hall,  Church  Hill  Tunnel,  bridges 
across  James  River  at  Snowden  and  Joshua  Falls,  high  bridge  at 
Farmville,  Va.,  Washington  Monument  foundations,  Capitol  Square, 
Richmond,  Va. 

HOWE'S  CAVE,  N.  Y.,  CEMENT. 

State  Capitol  Building,  Albany,  N.  Y. ;  Federal  Building,  Albany, 
N.  Y.  Waterworks  at  Albany,  N.  Y.,  at  Plattsburgh,  N.  Y.,  at 
New  Milford,  Conn.,  at  Cobleskill,  N.  Y.,  at  Ware,  Mass.  County 
Court  House,  Scranton,  Penn.  Used  exclusively  in  the  walls  of  the 
Hotel  Holland,  Fifth  Avenue  and  soth  Street,  New  York  City,  and 
in  the  Postal  Telegraph  Building,  New  York  City. 

BUFFALO,  N.  Y.,  CEMENT. 

In  City  of  Buffalo. —  Iroquois  Hotel,  Niagara  Hotel,  Buffalo 
Library,  St.  Louis  Church,  Church  of  the  Seven  Dolors,  Board  of 
Trade  Building,  Bank  of  Buffalo,  Bank  of  Commerce,  German  Insur- 
ance Building,  Erie  County  Penitentiary,  Erie  and  Niagara  Elevators, 
Trunk  Sewer,  and  Hertel  Avenue  Sewer,  both  8  ft.  diameter,  New 
York  State  Asylum,  Inlet  Pier  and  Waterworks  tunnel  under  the 
Niagara  River,  one  of  the  most  difficult  under-water  constructions  in 
the  world  ;  Buffalo  General  Hospital,  Erie  County  Almshouse, 
Buffalo  Medical  College. 

Towers  of  Suspension  Bridge,  Minneapolis,  Minn.;  Kokomo  Gas 


AMERICAN    CEMENTS.  '293 

Works,  Kokomo,  Ind. ;  Court  House,  Dansville,  111. ;  Court  House, 
Hamilton,  Ont.,  State  House  of  Correction,  Ionia,  Mich. ;  piers  of 
Erie  Railway  Bridge,  Portage,  N.  Y. ;  Soldiers'  Home,  Bath,  N.  Y. 

Federal  Buildings,  —  Post-offices,  Buffalo,  N.  Y. ;  Cleveland, 
Ohio,  Pittsburgh  and  Alleghany,  Penn. 

U.  S.  Government  Work.  —  Falls  of  St.  Anthony ;  Mississippi 
River,  Minn.;  Rock  Island  Arsenal,  Rock  Island,  111. 

The  dams  in  the  Missouri  River  at  Great  Falls,  Mont. 

AKRON,  N.  Y.,  CEMENT. 

Bridges.  —  Railroad  bridge  over  the  Hudson  River  at  Pough- 
keepsie  ;  cantilever  and  suspension  at  Niagara  Falls,  N.  Y. ;  Connec- 
ticut River,  Windsor  Locks,  Conn. ;  Mississippi  River  at  Burlington, 
Iowa,  at  St.  Louis,  Mo. ;  Red  River  at  Fulton,  Ark. ;  great  viaduct 
over  the  Cuyahoga  River  at  Cleveland,  Ohio  ;  waterworks  tunnel  under 
Lake  Michigan  at  Chicago,  111. ;  elevated  tracks  and  bridge  over  the 
Genesee  River  at  Rochester,  N.  Y. ;  waterworks  reservoir,  Buffalo, 
N.  Y. ;  City  and  County  Hall,  Buffalo,  N.  Y. ;  Grand  Central  Depot, 
New  York,  N.  Y. 

UTICA,  ILL.,  CEMENT. 

Chicago  Buildings. —  Armour  &  Dole  Elevators,  Central  Eleva- 
tors A  and  B,  Hough  &  Galena  Elevators,  Chicago  Board  of  Trade, 
Pullman  Works,  Rialto  Office  Building,  Pullman  Office  Building, 
Rookery  Office  Building,  Home  Insurance  Building,  Chicago  Public 
Library  Building,  Woman's  Temple,  Illinois  Steel  Company,  South 
Chicago. 

Indianapolis,  Ind. —  Big  Four  Round  House,  Home  Brewing 
Company  Building,  Park  Theatre,  New  Hospital,  Indiana  State 
Prison,  Michigan  City,  Ind. 

Kansas  City,  Mo. —  Y.  M.  C.  A.  Building,  Keith  &  Perry  Building. 

Saint  Joseph,  Mo. —  United  States  Government  Building. 

Omaha,  Neb. —  New  York  Life  Insurance  Building,  City  Hall, 
Paxton  House,  Murry  House,  Millard  House. 

Denver,  Col. —  State  House,  Union  Depot,  The  Windsor,  The 
Albany,  The  Equitable  Insurance  Company  Building. 

Pueblo,  Col. —  Opera  House,  Board  of  Trade  Building,  Union 
Depot. 


294  AMERICAN    CEMENTS. 

Des  Moines,  Iowa. —  State  Capitol,  Y.  M.  C.  A.  Building,  Dam  in 
Des  Moines  River. 

St.  Paul,  Minn. —  Ryan  Hotel,  New  York  Life  and  Germania 
Life  Insurance  Company  Buildings,  Manhattan  Building,  Pioneer 
Press  Building,  Globe  Building,  Lowery  Arcade,  Union  Depot,  Gas 
Works,  Endicott  Arcade,  Germania  Bank  Building. 

Minneapolis,  Minn. —  Union  Depot,  New  York  Life  Insurance 
Building. 

Duluth,  Minn. —  Hotel  Saint  Louis,  Spalding  House,  Board  of 
Trade  Building,  Court  House  and  Jail. 

MANKATO,  MINN.,  CEMENT. 

Federal  Buildings  at  Duluth,  St.  Paul,  and  Mankato,  Minn.; 
Ashland,  Wis. ;  Fort  Dodge,  Cedar  Rapids,  and  Sioux  City,  Iowa; 
Fremont,  Neb. ;  Sioux  Falls,  So.  Dak. ;  Fargo,  No.  Dak.  Bridge 
across  Mississippi  River  at  Redwing,  Minn. ;  across  the  Blue  Earth 
River  at  Mankato,  Minn.  State  Insane  Asylum,  Independence,  Iowa, 
and  at  Fergus  Falls,  Minn.  Railroad  Bridge  crossing  the  Mississippi 
River  at  Plattsmouth,  Neb.  Waterworks,  Minneapolis,  Minn.  Irri- 
gation Canals  at  San  Bernardino  and  Riverside,  Cal.,  and  State 
Capitol  Building  at  St.  Paul,  Minn. 

CUMMINGS  CEMENT,  AKRON,  N.  Y. 

Federal  Buildings. —  Jackson,  Tenn. ;  Macon,  Ga. ;  Aberdeen, 
Miss.;  Waco,  Tex.;  Port  Royal,  S.  C. ;  Clarksburg,  W.  Va.;  Harrison- 
burg,  Va. ;  Detroit,  Mich. ;  Youngstown,  Ohio. 

United  States  Government  Work. —  Sacket's  Harbor,  N.  Y., 
and  Buffalo  Harbor,  Buffalo,  N.  Y. 

Trumbull  County  Court  House,  Warren,  Ohio;  Dana's  Music 
Hall,  Warren,  Ohio;  Otis  Steel  Company  and  Cleveland  Rolling 
Mill  Company  Buildings,  Cleveland,  Ohio ;  New  City  Hall,  Goodale 
Block,  Burdick  Block,  Flower  Block,  Watertown,  N.  Y. ;  Herrin  & 
Sons  Paper  Mills  and  Dam,  Great  Bend,  N.  Y. ;  Dexter  Paper  Com- 
pany Buildings  and  stone  arch  raceway,  Dexter,  N.  Y. ;  Globe  Paper 
Mills,  Brownville,  N.  Y. ;  Bridge  at  Black  River,  N.  Y. ;  Ursuline 
Convent  of  the  Sacred  Heart  Buildings,  and  the  Episcopal  Church 
Building,  Youngstown,  Ohio ;  the  Great  Eads  Bridge,  St.  Louis, 


AMERICAN    CEMENTS.  295 

Mo. ;  County  Alms  House,  Rome,  N.  Y. ;  Diamond  Match  Company 
Buildings,  Oswego,  N.  Y. ;  Faxton  Hospital,  Utica,  N.Y.;  Hoosac 
Tunnel,  Mass. ;  Niagara  Falls  Paper  Company  Buildings,  Niagara 
Falls,  N.  Y. ;  Erie  County  Savings  Bank  Building,  Buffalo,  N.  Y.; 
City  and  County  Hall,  Buffalo,  N.  Y.  ;  waterworks  standpipe  at 
Delphos,  Ohio,  and  Akron,  N.  Y. ;  reservoir  waterworks,  Fredonia, 
N.  Y. ;  Atlanta  Brewing  Company,  Atlanta,  Ga. ;  Chattanooga  Brew- 
ing Company,  Chattanooga,  Tenn. ;  Sebald  Brewing  Company,  Mid- 
dletown,  Ohio  ;  Gerst  Brewing  Company,  Nashville,  Tenn. ;  Brenner 
Brewing  Company,  Covington,  Ky. ;  old  and  new  Croton  Aqueducts, 
New  York(6i3,ooo  barrels);  Grand  Central  Depot,  New  York,  N.  Y.; 
N.  Y.  C.  &  H.  R.  R.  bridge  over  the  Hudson  River  at  Albany,  N.  Y. 
Waterworks  dam  at  Willimantic,  Conn. ;  the  great  International 
bridge  crossing  the  Niagara  River  at  Buffalo,  N.  Y.,  and  the  suspen- 
sion and  cantilever  bridges  at  Suspension  Bridge,  N.  Y. 

Buildings  in  New  Castle,  Penn. —  The  New  Castle  Steel  and 
Tin  Plate  Company  (largest  tin  mill  in  the  world),  the  New  Castle 
Wire  Nail  Company,  Shenango  Valley  Steel  Company,  New  Castle 
Tube  Company,  Arethusa  Iron  Works,  Atlantic  Iron  and  Steel 
Company,  Shenango  Glass  Company,  Lawrence  Glass  Company, 
New  Castle  Water  Company,  Pearson  Building,  Boyles'  Block, 
St.  Cloud  Hotel. 

Heavy  stone  masonry  on  the  new  Erie  Canal  improvements,  and 
for  concrete  pavement  work,  over  125,000  barrels  yearly. 

FORT  SCOTT,  KAN.,  CEMENT. 

Federal  Buildings.  —  Kansas  City,  Mo. ;  Atchison,  Fort  Scott, 
Salina,  Fort  Leavenworth,  Fort  Riley,  Kan. ;  Camden,  Ark.  ;  Pueblo, 
Col. ;  Fort  Crook,  Neb. 

Buildings  in  Kansas  City,  Mo. —  New  England  Life,  New 
York  Life,  Insurance  Buildings,  Union  Depot,  Kansas  City  Journal, 
Board  of  Trade,  American  National  Bank,  Hotel  Brunswick,  Coates 
House,  Public  Library,  Gibraltar,  Massachusetts,  Nelson,  Bayard, 
Baird,  Peet  Bros.,  Kansas  City  Star,  and  Waterworks  Build- 
ings. The  Dold,  Fowler,  Allcutt,  and  Armour  Packing  Company 
Buildings. 

State  Capitol  Buildings  at  Topeka,  Kan.,  and  Austin,  Tex., 
County  Court  Houses,  Fort  Worth  and  Dallas,  Tex. ;  Warrensburg, 


296  AMERICAN    CEMENTS. 

Chillicothe,  and   Clinton,  Mo. ;    National    Soldiers'   Home,   Leaven- 
worth,  Kan. ;  Union  Depot,  Omaha,  Neb. 

Waterworks.  —  Lamar,  Boonville,  and  Kansas  City,  Mo. ;  Par. 
sons,  Coffeyville,  St.  Mary's,  and  Horton,  Kan. ;  Yocum  and  Cisco, 
Tex. ;  Missouri  River  Bridge,  Jefferson  City,  Mo. 

MILWAUKEE,  WIS.,  CEMENT. 

Minneapolis,  Minn.  —  Stone  arch  bridge  over  Mississippi  River, 
Hennepin  County  Court  House  and  City  Hall,  dams  and  retaining 
walls  of  the  St.  Anthony's  Falls  Water  Power  Company,  the  Expo- 
sition Building,  Guaranty  Loan  and  Trust  Building,  Union  Depot. 

St.  Paul,  Minn.  —  Ramsey  County  Court  House  and  City  Hall, 
Robert  Street  Bridge,  and  the  Chicago  and  Great  Western  Railway 
Bridge  over  the  Mississippi  River,  Globe  Building. 

United  States  Government  Locks  at  Sault  Ste.  Marie,  Mich. 

Milwaukee,  Wis. —  City  Hall,  City  Library,  Pabst  Building. 

Omaha,  Neb.  —  Bee  Building,  City  Hall,  American  Water- 
works' Basins. 

Duluth,  Minn.  —  Masonic  Temple,  Lyceum  Building,  Union 
Depot. 

Chicago,  III.  —  Chamber  of  Commerce,  Rookery  Building,  Home 
Insurance  Building,  C.  B.  &  Q.  General  Office  Building. 

Federal  Buildings.  —  Milwaukee,  Wis. ;  Omaha,  Neb. ;  and 
Duluth,  Minn. 

LOUISVILLE,  KY.,  CEMENT. 
UNITED  STATES  GOVERNMENT  WORK. 

Locks  and  Dams.  —  On  Muskingum  River ;  Muscle  Shoals, 
Tennessee  River;  Warrior  River;  Kentucky  River;  Kanawha River; 
Big  Sandy  River;  Illinois  River;  Ohio  River  below  Pittsburgh; 
Monongahela  River,  Pittsburgh  ;  Sault  Ste.  Marie ;  Canal  around 
Falls  of  the  Ohio  at  Louisville. 

Custom  Houses. —  Cincinnati,  Ohio;  St.  Louis,  Mo.;  Louisville, 
Ky. ;  Memphis,  Tenn. ;  Chattanooga,  Tenn. 

Bridges. —  P.  H.  R.  R.  connecting  bridge  over  the  Ohio  at  Pitts- 
burgh ;  B.  &  O.  R.  R.  bridge  over  the  Monongahela  above  Pitts- 
burgh; P.  H.  R.  R.  at  Steubenville,  Ohio;  N.  &  W.  R.  R.  at 


AMERICAN    CEMENTS.  297 

Kenova,  W.  Va. ;  L.  &  N.  R.  R.  at  Cincinnati,  Ohio  ;  C.  &  O.  R.  R. 
at  Cincinnati,  Ohio;  Suspension  Bridge  at  Cincinnati,  Ohio;  Cincin- 
nati &  Newport  Bridge  at  Cincinnati ;  Pennsylvania  R.  R.  Bridge  at 
Louisville,  Ky. ;  Kentucky  &  Indiana  Bridge  at  Louisville,  Ky.; 
Louisville  &  Jeffersonville  Bridge  at  Louisville,  Ky. ;  L.  &  N.  R.  R. 
at  Henderson,  Ky.;  I.  C.  R.  R.  at  Cairo,  111.;  K.  C.  &  M.  R.  R.  at 
Memphis,  Tenn. ;  Tennessee  River  Bridge  at  Chattanooga;  Eads 
Bridge  at  St.  Louis;  Merchants  Bridge  at  St.  Louis;  C.  B.  &  Q. 
R.  R.  Bridge  at  Alton,  111. ;  C.  B.  &  Q.  R.  R.  Bridge  at  Bellefontaine, 
Mo. ;  C.  B.  &  Q.  R.  R.  Bridge  at  Leavenworth,  Kan. ;  Illinois  Cen- 
tral R.  R.  Bridge  at  Yazoo  River,  Miss.;  Northern  Pacific  R.  R. 
Bridge  at  Minneapolis,  Minn.;  N.  C.  &  St.  L.  R.  R.  Bridge  at 
Bridgeport,  Tenn.;  Bridge  over  Missouri  River  at  Sioux  City,  Iowa; 
Railroad  Bridges  at  Dubuque,  Davenport,  Clinton,  Fort  Madison, 
Burlington,  and  Keokuk,  Iowa. 

Waterworks,  Dams,  etc. — Chattahoochee  River  Dam,  Colum- 
bus, Ga. ;  Hot  Springs  Waterworks  Dam,  Hot  Springs,  Ark.  ;  Little 
Rock,  Ark.,  Dam;  Covington,  Ky.,  Reservoir;  Nashville,  Tenn., 
Reservoir;  Minneapolis,  Minn.,  Waterworks;  St.  Anthony  Falls 
Tunnel;  St.  Louis,  Mo.,  Waterworks;  Little  Falls,  Minn.,  Dam. 

Public  Buildings.  —  Stale  House,  Indianapolis,  Ind. ;  State 
House,  Springfield,  111. ;  State  House,  Lansing,  Mich. ;  State  House, 
Atlanta,  Ga. ;  State  House,  Austin,  Texas. 

Tunnels.  —  Tunnel  under  Chicago  River,  Chicago,  111.;  Cleve- 
land Waterworks  Tunnel;  Sanitary  Drainage  Canal,  Chicago,  111.; 
Sea  Wall  Foundation  Lincoln  Park,  Chicago,  111. ;  Lake  Shore  Drive 
Sea  Wall,  Chicago,  111. ;  Palmer  House  Gas  Receiver,  Chicago,  111.  5 
Farwell  Block,  Chicago,  111. ;  Dock,  San  Diego,  Cal. 

ROSENDALE,  N.  Y.,  CEMENT. 

New  York,  N.  Y.  —  High  Bridge,  Harlem  River;  New  York  & 
Brooklyn  Bridge;  Washington  Bridge,  Harlem  River;  Madison 
Avenue  Bridge,  Harlem  River;  Second  Avenue  Bridge,  Harlem 
River;  American  Museum  of  Natural  History;  Astoria  Hotel  — 
Largest  in  the  World ;  Washington  Life  Insurance  Building ;  Co- 
lumbia College  —  New  Buildings;  New  Park  Row  Office  Building  — 
Thirty  Stories;  New  York  University  Buildings;  Astor's  New  Ex- 
change Court  Building ;  Post-Office ;  Custom  House ;  Equitable 


298  AMERICAN    CEMENTS. 

Building;  Mutual  Life  Insurance  Building;  Public  School  Build- 
ings ;  New  York  Athletic  Club  Building. 

Boston,  Mass. —  Subway;  State  House,  Bulfinch  Front;  Tre- 
mont  Temple;  Parker  House  Extension;  Suffolk  Bank  Building; 
Austen  &  Doten  Warehouse;  Brookline  Sewer  Work;  Metropolitan 
Sewerage  Extension ;  Metropolitan  Water  Board  —  Nashua  Aque- 
duct; Sewer  Department;  Water  Board  Department;  Paving  De- 
partment ;  Sudbury  Building ;  Warren  Chambers ;  Metropolitan 
Warehouse  Company ;  Conduit  Work  by  West  End  Street  Railway 
Company;  Boston  Electric  Light  Company;  Edison  Electric  Com- 
pany; West  End  Power  Station,  Charlestown  ;  Edison  Power  Sta- 
tion, Atlantic  Avenue  ;  Union  Terminal  Station. 

Pittsburgh,  Perm.  —  Post-Office;  Court  House  ;  Carnegie 'Mills; 
Davis  Island  Dam ;  Monongahela  Bridge. 

Washington, D.  C. —  Capitol ;  Bureau  of  Engraving  and  Printing; 
New  Patent  Office  ;  New  Pension  Building ;  Navy,  War,  and  State  De- 
partment Building  ;  Washington  Waterworks  ;  Treasury  Building. 

United  States  Government  Work.  —  Fortifications :  Fort  Dela- 
ware; Fort  Montgomery;  Fort  Jackson;  Fort  Adams;  Fort  Sum- 
ter;  Fort  Trumbull;  Fort  Taylor;  Fort  Warren;  Fort  Jefferson; 
Fort  Wadsworth ;  Fort  Preble ;  Fort  Monroe  ;  Fort  Hamilton ;  Fort 
Washington;  Fort  Knox  ;  Fort  Morgan;  Governor's  Island ;  Tybee 
Island;  Amelia  Island;  Fisher's  Island;  Garden  Keys;  Hawkins' 
Point ;  Pensacola ;  North  Point ;  San  Francisco ;  Gull  Island ; 
Sandy  Hook;  Newport  Harbor;  Plattsburgh  ;  Portland,  Me.;  Key 
West;  Finn's  Point. 

Navy  Yards.  —  Brooklyn ;  Norfolk. 

Rivers.  —  Allegheny ;  Ohio  ;  Kanawha. 

Dams  and  Waterworks.  —  New  Haven,  Conn.;  Holyoke? 
Mass.;  Mechanicsville,  N.  Y.;  Rochester,  N.  Y. ;  Pottstown,  Penn.; 
Pen  Yan,  N.  Y.;  Canandaigua,  N.  Y. ;  Dunnings,  Penn. ;  Kittanning 
Point,  Penn.;  New  Milford,  Conn.;  New  York  City,  Jerome  Park 
Reservoir;  Boston,  Mass. 

Sotith  Carolina  Cotton  Mills. —  Spartan  Mills,  Spartansburgh  ; 
Pacolet  Mills,  Pacolet ;  Pelzer  Mills,  Pelzer ;  Clifton  Mills,  Clifton; 
Columbia  Mills,  Columbia;  Reedy  River  Mills,  Mauldins ;  D.  E. 
Converse  Mills,  Glendale;  Union  Mills,  Union  ;  Pelham  Mills,  Maul- 
dins;  Fingerville  Manufacturing  Co.,  Fingerville. 


AMERICAN    CEMENTS.  299 

This  is  indeed  a  wonderful  record,  and  it  is  but  the  culmination 
of  four  thousand  years  of  successful  usage  of  Rock  cements. 

It  is  the  refutation  of  all  the  baseless  theories,  false  reasoning, 
and  untenable  analogies  which  have  been  evolved  from  the  high  short- 
time  tests  of  Portland  brands. 

This  marvelous  record  is  the  final  justification  of  American 
Rock  cements,  which,  setting  slowly  at  first,  nevertheless,  owing  to 
their  smooth  and  pasty  consistency  and  greater  volume  per  pound, 
attain  in  time  a  stone-like  durability  impossible  to  the  brittle,  quick- 
setting,  and  glassy  Portlands. 

The  latter  are  an  experiment  begun  seventy-three  years  ago,  and 
the  history  of  it  is  strewn  with  failures. 

The  former  have  been  made  through  centuries  which  disclose 
no  recorded  failure,  and  time  but  adds  to  the  proof  of  merit. 

If  long  experience  is  to  be  a  guide,  the  conclusion  is  irresistible 
that  for  substantially  all  the  manifold  purposes  for  which  a  cement 
is  used,  none  has  yet  been  produced  equal  to  the  AMERICAN 
ROCK  CEMENTS. 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 


AN     INITIAL     FINE     OF    25    CENTS 

WILL  BE  ASSESSED  FOR  FAILURE  TO  RETURN 
THIS  BOOK  ON  THE  DATE  DUE.  THE  PENALTY 
WILL  INCREASE  TO  5O  CENTS  ON  THE  FOURTH 
DAY  AND  TO  $1.OO  ON  THE  SEVENTH  DAY 
OVERDUE. 


101933 
.W   22  1934 


M. 


LD  21-50rw-l,'38 


